Kenneth Welsh's career was fast approaching an incredible two hundred and fifty different professional credits, and his was a face I recognize from a whole lot of something somethings. (FYI: I don't just watch genre stuff, folks, and this guy was a bit of a legend in my mind.) His characters were big and small, in all honesty, though I'd have to profess I think he gravitated more toward a few bigger-than-life (in a good way but occasionally menacing). His IMDB.com profile lists his award acknowledgements, and I'm honestly surprised it was so few.
In any event ...
I think he probably made his presence know (professionally) in some mainstream fare, but genre stuff followed very, very quickly. Fans might recognize him -- from the 1980's -- in such projects as Of Unknown Origin (1983), Seeing Things, The Ray Bradbury Theatre, and the late 1980's incarnation of The Twilight Zone. But, yes, it was probably his work aboard Twin Peaks that truly put him on the map: his work as the curious 'Windom Earle' -- one of Agent Cooper's mentors -- needed a bit more screen time (so far as this viewer is concerned), but -- at this juncture -- it is what it is, as they say.
But his contributions to Science Fiction, Fantasy, and Horror never quite stopped.
Beyond Reality. Timecop (1994). The X-Files. The Outer Limits. Eerie, Indiana. Witchblade. ReGenesis. The Day After Tomorrow (2004). Smallville. Stargate: Atlantis. Bionic Woman. Haven. The Expanse. Even the gloriously tepid Star Trek: Discovery. These are all places you can go -- and there are still more -- with which to enjoy the man's talent, and you'll likely realize that he always brought his best work to even the shortest scenes.
Alas, none of us lasts forever ... but his screen work will always endure.
Thoughts and prayers to the actor's friends and family.