How to drive my promotion discussion with my new manager?

Sorry to hear this - This is a very common occurrence (it's something I've faced myself), and it is extremely likely with a new manager who doesn't really get you yet.

First, I recommend the following discussions about manager mis-alignment - A lot of the concepts I cover there apply here as well:

• "Manager and I were misaligned about my promotion - How do I remedy this?"
• "My manager and I don't see eye-to-eye. How can I improve this relationship?"

With those out of the way, here's your goal at a high level:

1. Don't come off as accusatory.
2. Understand the delta between your manager's perception of your performance and your own understanding of your performance.

Not Coming Off As Accusatory

• A common first instinct in this scenario is to go in charging and start challenging your manager's points by saying, "Well actually, I did do this." If you have this instinct, you absolutely have to suppress it.
• Unless your manager is clearly bad/evil, then assume good intent. Managers are extremely busy people - It's very common for them to miss things and not realize the full extent of your accomplishments. Whenever you interact with your manager about this, weave this into how you carry yourself and communicate.
• Always go into every discussion acknowledging that there is potentially something you could have done better. When it comes to performance review and especially promotion, the common culprit is not having enough visibility around your work. We have a video about how to do that properly here: Make Sure To Do This To Get Full Credit For Your Work

Understanding The Delta

• I would ask something like this to your manager word-for-word: "Thanks for the feedback around my performance! For each of these points, can you give me some clear examples of what I could do to satisfy each of requirements at a senior level?"
• For the above, make sure that you make their feedback as crystal clear as possible. Let's say that they say that you need to show more growth among your more junior teammates. A good follow-up is: "What concrete results do I need to show to get full recognition here? Do they need to write great feedback for me in performance review (and what kind of things should they say about me)? Do I need to get at least 1-2 junior engineers promoted?" Keep asking follow-up questions politely until you exactly know what the "victory" conditions are like.
• Once you have a very clear understanding of your manager's perception of you, you can bring up your point of view where applicable with as much evidence as possible. Let's take the mentorship example and say your manager brought up that you need feedback from junior engineers around how you improved their code quality. If you have actual "receipts" around that, you can say something like, "Got it! I have actually spent the past half mentoring 2 junior engineers, and here's the feedback they have for me. Here's my old manager's feedback around my mentorship impact as well. Is there anything I'm missing here?" The last part is to open the door for you being wrong (showing humility) while still making the case for yourself.

Great advice from Alex on this question. Regarding "Understanding The Delta", here's a tool you can try:

Ask your manager if he'd be open to starting a draft of your promo packet doc even if he doesn't think you're ready for promo yet. The draft can serve as a spec for where you're meeting the bar and where there are perceived gaps. It's an easy way for the two of you to stay on the same page and reduce the work needed when it comes time to put you up for promo. Think of it as the TDD version of career advancement.