I just started working at a company about two months back fresh out of graduate school. There is one ex-colleague back in the graduate school who’s striving to land a job. I’d be more than happy to provide help in the process if one is my friend or at least a neutral acquaintance who maintains an amicable relationship with me. But this ex-colleague made my grad life quite miserable by throwing me under the bus several times. He also affected a couple of other colleagues of mine. I maintained strong, meaningful relationships with my advisor, other colleagues in the lab and outside so it helped me go through those years.

Now that I am out of grad school, I feel much better mentally and don’t want to cross paths with him by any means. So, here is the problem. I’m working at a top-level company that a lot of grad students in my (and his) field want to work at. He’ll probably try to apply here again. Given the size of this company, we are highly unlikely to work together even if he somehow gets a job here. But I think there is quite a high chance that we might somehow interact through company networking events or whatnot. I absolutely do not want to have him in my life anymore.

My question is would it be okay to tell my hiring manager that I do not really want to be around him if he ever applies in the future so somehow he could communicate with other hiring managers to not let him in?

Thank you.

Thank you all for providing honest feedback. As someone mentioned, I’m pretty new to this professional world. Grad school is kind of in the gray zone. I will not worry over the probability and give not too much power to him over my own life. Easier said than done. Having said that, I’m capable and once I’m determined I’m a go-getter. If he ever somehow gets a job here and is placed into my division (most likely if he’s offered a job), I will start planning some solid action plans. To be clear, I don’t mind working with people I don’t click with or dislike. I have quite a bit of experience and learned a very good lesson and applied it, resulting in successful collaborations and even developing friendship. These people weren’t bad nor toxic. They did not try to harm me. However, He’s just “toxic”. Hypothetically he gets into my division and somehow we start doing some collaboration. Hopefully by then I have thick enough skin to deal with his presence, remain nonchalant about our past, and even become super agile to detect any potential emerging back-stabbing plans. If not, I will just apply to a different company, not transferring within the company. Some might think that it’s too much but I care about my mental sanity. Dealing with a narcissist wasn’t fun.

  • 4
    How long ago was grad school? In what ways did he "affect" your other colleagues? How old is he?
    – jmorc
    Mar 24, 2022 at 13:33
  • 5
    If you and the hiring manager do have a discussion, consider how to present you assessment of the ex-colleague in a non-emotive manner when flagging there could be a problem. e.g. "He was not a team player which impacted the work of other grad students" contains more information than "he was an **** known for throwing people under the bus", even if both are true.
    – traktor
    Mar 24, 2022 at 23:00
  • 4
    @traktor - I'd say that completelly depends on the relationship with the manager. If I said something like that first statement to my current manager, he would probably laugh and respond like "what the fuck are you saying"? We have a good, friendly relationship and go drinking together at work events. Saying "no, that guys was an asshole" would be completelly normal for us.
    – Davor
    Mar 25, 2022 at 11:05
  • 2
    Can you add some information about the size of the top-level company in terms of (approximate) number of employees and the number of business units/(physical) sites? Do they have 100, 10,000 or 1 million employees? (But without "Edit:", "Update:", or similar - the question should appear as if it was written today.) Mar 25, 2022 at 11:33
  • Since you mention it's a large company, it's extremely unlikely that your manager will even get informed if that person gets hired, much less have any influence over that decision.
    – Therac
    Mar 25, 2022 at 21:46

9 Answers 9


would it be okay to tell my hiring manager that I do not really want him if he ever applies in the future so somehow he could communicate with other hiring managers to not let him in

No, this would be incredibly unprofessional. You had some personal conflicts with this guy, but that doesn't mean that you get a veto over whether he works for your employer or not (note: absolutely not "your company", you don't own it).

What you could do here is to explain to your manager that you have had personal conflicts in the past and you wish not to work with him. The difference here is that you are stating facts (or at least, your opinion) about what happened, but letting other people make the decisions about what to do. You do not get to set your employer's hiring policies.

(The exception here is obviously if the conflicts went beyond a personal level - for example, if they had physically assaulted you. But that doesn't sound like that's what's happened here)

  • 33
    I completely disagree. We're talking about a guy who throws people under the bus. Whether OP likes him or hates him is irrelevant; OP thinks he's toxic and should blackball him. Mar 24, 2022 at 11:40
  • 41
    @A.I.Breveleri Yes but the OP doesn't get to tell his manager what to tell hiring mangers to do, which is the suggestion in the question. They should state their (biased) opinion of the world and let the hierarchy deal with it - it's up to them to decide how to deal with the information they've been given, not up to the OP to decide the hiring policy for a company. Mar 24, 2022 at 12:10
  • 14
    As I understand it, the problem is turning a problem of yours into a problem of the company. That isn't right. However, in some cases, avoiding a problem to the company by providing relevant information is useful and professional.
    – Hermes
    Mar 24, 2022 at 12:17
  • 10
    @Hermes which is what the second paragraph does, as any good manager at that point will respond with "Ahhh. Very interesting. Tell me more". While there are circumstances in which it is justified going around the official chain of command if your manager doesn't respond in that way, the OP doesn't sound experienced enough to know when that would be a good idea. Mar 24, 2022 at 12:31
  • 3
    Oh, sorry, @PhilipKendall, I was trying to explain your point in another way, because I feel that it can be misunderstood. I agree with you.
    – Hermes
    Mar 24, 2022 at 12:36

Tell you manager "I've worked with this person before, there were a lot of issues both with me and with other people, and I would be uncomfortable working with them if they start working here".

Then leave it at that.

  • 2
    That's in my opinion exactly the correct level. A reasonable manager would then ask you questions, and you should answer all questions honestly and truthfully.
    – gnasher729
    Mar 26, 2022 at 15:38

You sound almost paranoid.

The likelihood that the person applies, gets a job and you may have to interact with him are minimal. By worrying about this unlikely scenario you give them a lot of power over your own life. Don't do this!

Focus on your career and being successful in your new role and forget about them. If that person ever shows up in your life again, react to it on a case by case basis. If you are asked for a reference, you can give an honest (but unemotional and factually correct) one. If you are not asked, don't say anything. If you are asked to work with them, focus on the work and set boundaries.

Look, you had a negative experience but you need to learn how deal with negative people or people you don't like in a professional setting. People can't exert power over your life unless you let them, especially if they have no formal authority.

It's time to learn from the experience, figure out what to do if you run into someone like this again and move on.

would it be okay to tell my hiring manager that I do not really want him

No. You provide feedback only if asked.

  • 49
    "You sound almost paranoid" -- yes, some toxic, manipulative, narcissistic people can do that to you. "It can't be that bad" is what I read in these words -- and I assure you: Yes, it can be that bad. And the worst part is that you cannot really call them out nor warn people about them, neither on personal nor on a professional level; the reaction always is "It can't be that bad, you're badmouthing them" (unless you happen to talk to someone who has had the same experiences with a toxic person).
    – orithena
    Mar 25, 2022 at 9:21
  • 4
    (Please note that I'm only hung up on your first line here. The rest of the answer is correct in the possible course of action. Sadly.)
    – orithena
    Mar 25, 2022 at 9:25
  • 16
    OP does not sound paranoid. OP sound bullied. Mar 25, 2022 at 14:49
  • 4
    Incorrect on so many levels. Not expressing your concerns or talking about history with a potentially new co-worker to your manager is a recipe for "why didn't you tell us this earlier?" Phrasing will be important but, is not a reason to not bring it up especially if a lot of fellow grads apply to this same company.
    – IT Alex
    Mar 25, 2022 at 15:22
  • 1
    @ThorbjørnRavnAndersen I almost agree with you, and that "almost" is hung on a technicality. "Bullying", as I understand the term, is an open confrontation towards the victim (possibly hidden towards other people). I understand OPs source of paranoia (and possibly PTSD) as something more sinister: a hidden manipulation that only became clear to OP in retrospective. "Hidden bullying" or "subliminal bullying" might be a term for that.
    – orithena
    Mar 25, 2022 at 15:22

would it be okay to tell my hiring manager that I do not really want him if he ever applies in the future so somehow he could communicate with other hiring managers to not let him in?

No. It would not be OK. Whether or not this person lands a job at your company, you need to understand that in work (and in life) you're going to encounter people that you don't want to "deal" with. Always be professional.

  • 1
    You will encounter people, but people who have thrown you under the boss have no legitimate expectations not to be thrown under the bus by you. Being professional ≠ being a doormat.
    – gnasher729
    Mar 26, 2022 at 15:39

He’ll probably try to apply here again

Herein lies your problem. "Probably" isn't fact. And your manager can't operate on probability.

You can't control what others do. Tend to your own wellness, and there won't be any time to worry about what others might be doing. Get into a regular exercise routine. Join a gym. Eat better. Pursue personal goals outside of work. You would be amazed at how much getting into these habits will change not only your brain chemistry, but also your outlook on life and being able to cope.

There's always going to be someone on the job who annoys you. Soothe, encourage, and deal with yourself first.


Calm down. You don't know when he will apply and whether he will apply at all. Then he has to get the job and has to work close to you, to have any impact on you. (My company employs dozens of people I don't want to work with and apparently, I never have to do so.)
Do not do anything, unless you receive a message from the guy or have a joint meeting which means you are going to work together.

If this happens, you have to reconsider what to do. In a company one acts more on behalf of a team and less independent like in grad school. If he acts in bath faith, both his team and your team is affected. So other team members or even the bosses of both teams could support you.
In general, companies try to comply to no-harassment laws and try to get a professional, non-negative, healthy working environment.


You shouldn't do anything about this person before you know for sure that it's applying or has been hired into the same company as yours. I do understand how you feel and why you feel that way, but that's something you should work on for yourself, and not get the company involved beforehand.

Now, if this person applies for your company, there are a few things to consider before deciding how to act:

  • In some companies, bosses/managers/HR do find out when an actual employee might know a prospect candidate, and ask for their opinion. If that's the case, you should be completely honest but without trying to make it sound personal; in other words, do make clear that you know this person has some (very) toxic, unprofessional behaviours, and that he could be potentially problematic for the company, but try to avoid saying this person bullied specifically you, or targeted you, unless you're asked that.
  • In other companies, hiring process is quite private or revealled only to a handful of people; if this is the case, it's most likely that you wouldn't be among these people, so even if know from other sources that this person is applying, you shouldn't do anything until you actually have to work directly with him; then do the same as the previous point: do state the facts that you know him beforehand and you feel uncomfortable working with that person due to their toxic behaviour, and then let the managers handle it.
  • IF (and it's quite a big if) this person applies, gets hired, has to work with you, AND the managers dismiss all of your concerns, the best thing you can do is to be the "bigger person": work as professionally as you can, do all the activities that correspond to you the best way possible; but also have everything backed up by a traceable trail (paper, mail, etcetera), try to avoid any direct conflict or confrontation, make your managers aware and part of every possible issue that can be proven... in short, don't expect the worst but be prepared for the worst.

And as a side note: this person seems to have caused you more harm that you even might be aware of. You might need to take this to a therapist, as this issue has the potential to affect both your personal and professional life by making you nervous, anxious, maybe paranoid, without even having direct contact with this person. Be aware that this is not about "you forgiving him", but you overcoming the wounds this person left with its actions.

Best of lucks.


No. It is not OK. You would be seen as a whiner.

I absolutely do not want to have him in my life anymore.

This is your problem, not the company's. It is not the company's responsibility to make sure that you only have people working with you that you like.

  • The OP has made clear in the update that the issue goes well beyond "liking". A toxic coworker is costly to the company, as good workers leave.
    – donjuedo
    Mar 27, 2022 at 1:42

In addition to other advice you're received, keep in mind that anything that looks like an ultimatum may not work out the way you hope.

I once worked at a company where A and B were peers in [Department], but decidedly unfriendly. A left voluntarily to pursue other opportunities. After gaining more experience over the next few years, A applied to return as the new head of [Department], which would make A B's manager.

B got wind of this, and told the VP that they wouldn't report to A.

Soon, VP came to B and said, "well, we're hiring A, and since you've made your feelings clear, I already know that you'll be leaving soon. I'll give you time to find a new position and exit gracefully." This was not a conversation or negotiation - VP told B that B would be leaving.

Moral of the story: even if your manager likes you, if someone else with more clout than your manager really wants to hire your nemesis, well, if you've made your feelings clear, then you've made them clear, and may have to deal with the consequences. That's not necessarily a bad thing, but there it is.

  • 2
    I fully agree with that last line, "not necessarily a bad thing". If the end result for the OP were like B above, that's likely still better than working with the known toxic person.
    – donjuedo
    Mar 27, 2022 at 1:39

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .