I was wondering if some recruiters would see it as negative, thinking I might not be focused or committed to my permanent job if I had a freelance project on the side.
Obviously, more showable work experience is an advantage, but I'm wondering if I'm overlooking some disadvantages in listing concurrent freelance projects.
There are so many variables that it is hard to answer this question. How much time did you spend freelancing? Are you free-lancing in the same field as full-time work? Is your freelancing experience more valuable to me than your full-time experience? Do you plan on continuing to freelance after we hire you?
As a prospective employer, this does raise a potential red-flag for me. As the one paying you to work full-time, I expect to be your priority. When you have an alternative source of income, that competes more strongly for your priorities and time. You could potentially get the same experience with open-source or volunteer activities that would not be as much of a threat.
Employers (and therefore recruiters) may see shared intellectual property (IP) as an issue. If you apply for a salaried position as an information worker (software developer, artist, composer, etc), many companies will require you sign over all IP created while employed to that company. This will definitely affect your freelancing work.
Employers (and therefore recruiters) may also see it as a potential conflict of interest. Freelancing for a potential competitor is a big risk. Similarly, accidentally or deliberately using knowledge gained in your salaried work in your freelancing work is also a risk. Employers may also feel freelancing is a distraction from your day job.
That said, most will not care if the positions are unrelated (e.g. you are employed as a software developer but freelancing as an artist) or valuable to the company and you can manage your time well. Freelancing can give you different and better experience, particularly soft skills (e.g. dealing with customers, self promotion and managing expenses) and exposure to different markets, products and techniques.
It really comes down to how you sell yourself. If you are confident and can demonstrate that your freelancing experience makes you a better employee, recruiters will see it as a plus.
Don't worry too much about this. Many people have "side hustles," and it shows you have lots of motivation. There's no sense trying to pretend to be someone you are not. Be yourself.
Independent (commission-paid) recruiters' jobs are to represent the employer to you, so just ask them about how to present your best possible face to employers. If you think your side hustle might be an issue, ask. (You do have conversations with recruiters before they present you to employers, right? You should!)
Be aware that some employers won't want you to spend time on side hustles. They'll straightforwardly tell you that, and you can decide whether to proceed.
