Or is he just some actor who answered a “60-ish, graying, guitar player” audition ad?
-rainy
Thanks for asking this – I’ve been wondering the same thing.
pulls up a seat to wait for an answer
“Hey! I know that guy! That’s, uh, mm…”
pulls up a chair next to Twixter
“That’s not John Mayall, is it?”
“That guy from Quicksilver Messenger Service?”
John Mayall!! Man, how’d you pull that one up? Now I’ve got Room To Move in my head! Thanks!
It’s the hair color. 
I just saw a DVD of his 70th birthday concert, and no, it’s not him in the commercial. Good concert, no “Room To Move” (or “California”) though.
Wow! I should have recognized him, but wasn’t really paying attention.
I recognize the name – didn’t he write the thirtysomething theme, etc.? – but don’t think I’ve ever seen him in person.
It’s a good commercial, anyway – though of course, as a mere child of 51, I’m definitely not the target audience. 
W.G. Snuffy Walden wrote all the music for *Sports Night * as well, but I wouldn’t recognize him if I saw him on TV or on the street.