I went through the Apple product designer interview for an iOS apps team role last fall. It was my third Apple loop over the years (different teams, different levels). Here's what's consistent and what surprised me this time.
The portfolio review is the heart of the process. Apple spends more time on portfolio than almost any other company I've interviewed at. My final portfolio presentation was 45 minutes plus 30 minutes of Q&A. That's 75 minutes on my work, with a panel of 3-4 people.
What they're actually evaluating in the portfolio.
Process depth. They want to see the messy middle, not just the polished outcome. I showed an early wireframe that was wrong, why it was wrong, and what changed. That got more positive response than my final screens.
Decision rationale. For every major design decision: why that choice specifically, what alternatives you considered, what you'd do differently. They'll probe. "Why this layout and not a list view?" Have real answers.
Collaboration texture. Apple's design culture is highly collaborative across design, engineering, and PM. They'll ask how your designs changed because of an engineer constraint or a PM pivot. Showing that you worked with, not around, the rest of the team is important.
The HIG question. At some point someone will ask how you think about Apple's Human Interface Guidelines. Don't say you follow them religiously. They want to hear that you understand the principles behind them and can make reasoned tradeoffs. "The guidelines say X, but in this context I did Y because Z" is the answer they're looking for.
Interview structure. Recruiter call, portfolio review round (remote), onsite with 4-5 rounds (design challenge, design critique, cross-functional collaboration, behavioral). The design challenge is a real exercise: they give you a prompt the night before and you present the next morning. I got about 12 hours.
What tripped up my first loop years ago. I was too precious about the work. I got defensive when they pushed back on design decisions. Apple interviewers push back as a technique to see how you think, not because they've already decided you're wrong. Engage with the pushback, update your thinking if it's valid, hold your ground with reasoning if it's not.