Man, my memory is so unbelieveably bad; I can't remember which steelhead was my first...
There was the small dark "wild" summerrun? I caught and released on a silver/red vibrax several years ago while fishing for salmon on the Salmon during a hot bite when I hooked 4 or 5 fish in less than 30 minutes from the same hole including my biggest hatchery coho ever.
Then there was the late winter/spring/early summer? wild hen that I caught on the Sol Duc also a few years ago using a #8 pearl pink spin n glo (white wing) with a pink roe sack filled with loose eggs from discarded coho on the Bogachiel that were sampled for CWT.... most memorable fight of them all.
Then there was the chrome late hatchery winterrun that is tied for the most exciting jig caught fish, which I returned back to the Queets last Sunday of the season several years ago... I still have that jig and am reluctant to use it unless the situation calls for a jig like no other. I can't remember where I got it, but it's got an orangish head/hackle, sparkly pearl dub body and orange rabbit tail. Didn't get an opportunity to break it out this year.
Oh and why I say it's tied for first place as most exciting jig fish? I was fishing from the deeper side of the river and I saw a huge obstruction of sort not far from the bank in the clearish water. First cast, float down! Perfect cast, perfect drift.

The other steelhead that shared first place was caught on the Salmon with a hot pink beau mac 1/8 marabou jig. I was fishing from the snaggy side of the river with trees around me and the logjam upstream of me. There was a log right in the middle of the hole and it had some smaller woody debris hung up on it. First cast no good, tangled with branch. Second cast no good, overcorrected. Third time's the charm! I visualized the cast and the take in my mind. Then I cast. Right on the money!

Float drifts down to the sweet spot. Oh, oh, oh! Float down! Fish on! Turned out to be a small "wild" one.
Anyways, for the life of me, I'm embarassed that I can't remember which fish was the first ever steelhead.
And I haven't really caught a bonafide summerrun yet.