Four moves for the relationship, not a general essay on earning authority.
01
Don't compete with their expertise, use it
You weren't hired to know more than they do about the work. Trying to prove otherwise just invites a comparison you'll lose. Your job is direction and judgment calls, not being the most experienced person in the room.
02
Ask for their read before you decide, not after
Someone with more experience than you has usually seen this exact situation before. Asking early reads as good judgment. Asking after you've already decided reads as a courtesy call.
03
Make the actual decisions anyway
Deferring on everything to avoid friction isn't respect, it's abdication, and they'll notice faster than anyone. Ask for input, then decide, even when the decision differs from what they'd have picked.
04
Name the dynamic once, directly, if it's getting in the way
If you can feel them testing you, or working around you, a direct one-on-one conversation beats months of quietly absorbing it.
What This Isn't
This is different from managing a former peer, where the awkwardness comes from a relationship that changed overnight. Here, the person was never your equal in this role, they were more experienced from day one, and the tension is about competence, not history. That means the fix is different too: you don't need to renegotiate a relationship, you need to earn a specific kind of trust, that you'll use their expertise well and still make the call when it's yours to make.
If the Dynamic Needs Naming
"I want to check in on how this is working for you, me being newer to this than you are. I'm relying on your experience a lot, and I want to keep doing that. I also want to make sure it's clear when I'm asking for input versus when I've already decided, so neither of us is guessing. What's that felt like from your side?"