"I knew 'A Family Affair' was a B picture, but that didn't stop me from putting my all in it," Rooney recalled.
Studio boss Louis B. Mayer saw "A Family Affair" as a template for a series of movies about a model American home. Cast changes followed, most notably with Lewis Stone replacing Barrymore in the sequels, but Rooney stayed on, his role built up until he became the focus of the films, which included "The Courtship of Andy Hardy," ''Andy Hardy's Double Life" and "Love Finds Andy Hardy," the latter featuring fellow child star Garland.
He played a delinquent humbled by Spencer Tracy as Father Flanagan in 1938's "Boys Town" and Mark Twain's timeless scamp in 1939's "The Adventures of Huckleberry Finn."
Rooney's peppy, all-American charm was never better matched than when he appeared opposite Garland in such films as "Babes on Broadway" and "Strike up the Band," musicals built around that "Let's put on a show" theme.
One of them, 1939's "Babes in Arms," earned Rooney a best-actor Oscar nomination, a year after he received a special Oscar shared with Deanna Durbin for "bringing to the screen the spirit and personification of youth, and as juvenile players setting a high standard of ability and achievement."
He earned another best-actor nomination for 1943's "The Human Comedy," adapted from William Saroyan's sentimental tale about small-town life during World War II. The performance was among Rooney's finest.
"Mickey Rooney, to me, is the closest thing to a genius I ever worked with," ''Human Comedy" director Clarence Brown once said.
Brown also directed Rooney and Elizabeth Taylor in 1944's horse-racing hit "National Velvet," but by then, Rooney was becoming a cautionary tale for early fame. He earned a reputation for drunken escapades and quickie romances and was unlucky in both money and love. In 1942 he married for the first time, to Gardner, the statuesque MGM beauty. He was 21, she was 19.