Universal Pictures came calling, seeing in the team a modern Laurel and Hardy (though their appeal was more akin to Wheeler and Woolsey or Clark and McCullough). The team made more than a dozen films during the WWII years, mostly for Universal (and some on loan-out to MGM). They were light as air, mindless entertainment for wartime, and though critics lambasted them, the public flocked to see films like "One Night in the Tropics" (their first, 1940), "Buck Privates" and "Hold That Ghost" (both 1941), "Pardon My Sarong" (1942), "It Ain't Hay" (1943), and "Lost in a Harem" (1944). The team's classic "Who's on First?" routine was featured in the film "The Naughty Nineties" (1945). In the best of these films, the boys played good-natured bumbling schemers and con men, caught up in circumstances beyond their meager control. Good leads and supporting casts (e.g., The Andrews Sisters, Martha Raye, Joan Davis) helped, too.
With the end of WWII, the team's popularity slipped. This was not helped by the fact that they were put into increasingly juvenile, low-budget films for both Universal and on loan-out (twenty films from 1946 to the end of their career). In their better vehicles, the pair cavorted and double-talked through "Buck Privates Come Home" (1947) and Mexican Hayride" (1948). But mostly, the titles told it all: "Abbott and Costello Meet Frankenstein" (1948), "Abbott and Costello Meet Captain Kidd" (1952), "Abbott and Costello Go to Mars" (1953), and so on.
By the time of their last, "Dance with Me, Henry" (1956), Abbott and Costello were as tired of each other as their audiences were of them. They split acrimoniously in 1957, and Costello made one solo film, the fantasy "The Thirty-Foot Bride of Candy Rock" (1959). After one of his children drowned, Costello devoted much time to charity work in his native New Jersey and lost some interest in his career.
Abbott and Costello found a renewed audience on TV; not only were their films popular in reruns, but they briefly had their own "Abbott and Costello Show" (syndicated, 1952-1953). This show itself went into endless reruns, and was even turned into an animated series in 1966. Abbott and Costello also appeared on "The Colgate Comedy Hour" (NBC, 1951-1954). The two were tearfully reunited in a segment of "This Is Your Life" shortly before Costello's death.