My former manager and I did not get along for various reasons.
I've performed my role successfully based on the areas I have been accountable for.
Yet despite that, they are trying to influence my new manager by asking them to give me a poor performance review.
My new manager has told me that they disagree with my old manager's assessment of me, and will give me a positive performance review.
The issue I have is where old manager is influential and has been at the company for a long time. Where they have actively tried to influence other managers in a similar way, by back biting, and have been successful in doing so.
This has led to me being overlooked for promotions or general growth opportunities.
New manager has mentioned that there is nothing to worry about, and to follow their guidance. I am concerned that the damage has already been done, since old manager has already spoken poorly about me to other members of the leadership team, my boss's boss for example who has mixed feelings about me.
Old manager also sits on promotion panels, and I am concerned that they will be obstructive.
I am in two minds about leaving. On one hand, new manager may be able to help me improve my profile, but then I have the old manager who is constantly actively working against me.
New manager is new to this environment so influence is less at this moment in time with leadership team but could grow.
For anyone that has been in this situation, how do these situations typically play out if you decide to stay?
To put situation into context:
Old manager had a problem with the nature of the role itself. They were trying to change formally defined accountabilities in a coercive way, where I pushed back because I felt that it put me at a disadvantage and going against org guidelines.
New manager is much more respectful, and is assessing me based on these accountabilities , so no issues.