I did same… although oddly, not for the role I thought she’d won it for…
I misremembered her as having won one for The Color Purple. She was nominated, but didn’t win. She won for Ghost (which, in retrospect, seems kinda Marissa Tomei for My Cousin Vinny-ish… but then I don’t recall/care enough to look up who the competition was that year)
Minor point, but Gig Young’s Oscar came after “The Rogues”; however, fellow cast member on that show David Nevin’s came before. And if Gladys Cooper and Charles Boyer ever received one, which to be sure they should have, they would have received one before also.
Melissa Leo was a castmember on Treme before earning her Oscar for The Fighter, and of course kept showing up for work anyway.
Louise Fletcher from DS9 was another Oscar winning Trek actor. She won for "One Flew Over The Cuckoo’s Nest "
Mo’Nique got the Oscar for Precious: Based on the Novel “Push” by Sapphire and promptly made hundreds more episodes of The Mo’Nique Show.
Anne Baxter of ALL ABOUT EVE fame won an Oscar in the '40s for THE RAZOR’S EDGE, and by the '80s was a castmember on HOTEL with Connie Sellecca and James Brolin. (And in the '60s, Baxter showed up for more than half-a-dozen episodes of the Adam West BATMAN series; that doesn’t count toward the OP’s criteria, but why not mention it?)
Ray Milland got the Oscar for The Lost Weekend, and went on to play the lead character in the Meet Mr McNutley sitcom on CBS – before returning to CBS years later, to play the lead character in the Markham private-eye drama.
Dean Jagger: won the Oscar in 1950 for TWELVE O’CLOCK HIGH, then racked up Emmy nominations on television in the '60s as a MR NOVAK castmember.
Michael Douglas kept appearing in new episodes (including the opening credits) of that show even after winning an Oscar for One Flew Over The Cuckoo’s Nest.
Who the heck knew that TV legend Art Carney, after winning an Oscar for HARRY & TONTO, returned to television in LANIGAN’S RABBI, as an Irish Catholic police chief named Lanigan, solving crimes with help from his pal the amateur-sleuth rabbi?