Howard Morris (1919-2005)
His newswire obituary says comic actor Howard Morris is best known for playing lonesome hillbilly Ernest T. Bass, but true children of the television age revere Morris for his role as one of Sid Caesar's trusty supporting players on Your Show of Shows in the early '50s. Morris, in my mind, is probably best remembered for playing the clinging Uncle Goofy in a This is Your Life spoof, but his ability to play his part as a cog in the wheels of comedy was superlative, and his flexible voice made for a bounty of work in cartoon voiceover and character parts for years after.
My personal favourite Morris work is his narration of the Academy Award-winning cartoon short Munroe, based on the Jules Feiffer comic about a toddler who gets drafted into the U.S. army. Morris gives it a folksy spin, without overselling the humour of the situation.
Perhaps not a comic genius, per se, but a comedic technician of the highest order.