Question: who guest hosted for johnny carson?
Answer: Until Joan Rivers became permanent guest host in September 1983, the most frequent of "guest hosts" were: 'Joey Bishop' (177 times), Joan Rivers (93 times), Bob Newhart (87 times), John Davidson (87 times), David Brenner (70 times), McLean Stevenson (58 times), Jerry Lewis (52 times), and David Letterman (51 times).