Answer by taking a quote from the following article:

John Florence Sullivan (May 31, 1894 - March 17, 1956), known professionally as Fred Allen, was an American comedian whose absurdist, topically pointed radio program The Fred Allen Show (1932-1949) made him one of the most popular and forward-looking humorists in the Golden Age of American radio. His best-remembered gag was his long-running mock feud with friend and fellow comedian Jack Benny, but it was only part of his appeal; radio historian John Dunning (in On the Air: The Encyclopedia of Old-Time Radio) wrote that Allen was radio's most admired comedian and most frequently censored. A master ad libber, Allen often tangled with his network's executives (and often barbed them on the air over the battles) while developing routines whose style and substance influenced fellow comic talents, including Groucho Marx, Stan Freberg, Henry Morgan and Johnny Carson; his avowed fans also included President Franklin D. Roosevelt and novelists William Faulkner, John Steinbeck and Herman Wouk (who began his career writing for Allen).

Allen first hosted The Linit Bath Club Revue on CBS, moving the show to NBC and becoming The Salad Bowl Revue (in a nod to new sponsor Hellmann's Mayonnaise, which was marketed by the parent company of Linit) later in the year. The show became The Sal Hepatica Revue (1933-34), The Hour of Smiles (1934-35), and finally Town Hall Tonight (1935-39). In 1939-40, however, sponsor Bristol-Myers, which advertised Ipana toothpaste as well as Sal Hepatica during the program, altered the title to The Fred Allen Show, over his objections. Allen's perfectionism (odd to some, considering his deft ad-libs) caused him to leap from sponsor to sponsor until Town Hall Tonight allowed him to set his chosen small-town milieu and establish himself as a bona fide radio star.  The hour-long show featured segments that would influence radio and, much later, television; news satires such as Rowan and Martin's Laugh-In's "Laugh-In Looks at the News" and Saturday Night Live's "Weekend Update" were influenced by Town Hall Tonight's "The News Reel", later renamed "Town Hall News" (and in 1939-40, as a sop to his sponsor, "Ipana News"). The Tonight Show Starring Johnny Carson's "Mighty Carson Art Players" routines referenced Allen's Mighty Allen Art Players, in name and sometimes in routines. Allen and company also satirized popular musical comedies and films of the day, including and especially Oklahoma!. Allen also did semi-satirical interpretations of well-known lives--including his own.  The show that became Town Hall Tonight was the longest-running hour-long comedy-based show in classic radio history. In 1940, Allen moved back to CBS Radio with a new sponsor and show name, Texaco Star Theater, airing every Wednesday at 9:00 pm ET on CBS, then Sundays at 9:00 pm in the fall of 1941. By 1942, he shortened the show to half an hour, at 9:30 pm ET--under network and sponsor edict, not his own. He also chafed under being forced to give up a Town Hall Tonight signature, using barely known and amateur guests effectively, in favor of booking more recognizable guests, though he liked many of those. Guests included singers from Kingston, New York, the original woman behind the "Aunt Jemima" on pancake boxes, and more guests up the road--from Saugerties, like the singer, Donald Gardner.

Who did he host with?
In 1940, Allen moved back to CBS Radio with a new sponsor and show name, Texaco Star Theater, airing every Wednesday at 9:00 pm ET on CBS,