Astor was at the center of a scandal in 1936, when her suit for custody of her daughter Marylyn led to the disclosure of a personal diary, allegedly documenting her liaisons with a number of prominent Hollywood figures. The controversy did not destroy her career, however; indeed, in many ways it peaked with a series of splendid and acclaimed second lead and occasional lead performances as passionate, driven women in such fine dramas and comedies as "The Prisoner of Zenda" (1937), "Midnight" (1939) and "The Palm Beach Story" (1942). She deservedly won a Supporting Actress Oscar as a bitchy pianist rival of Bette Davis for the affections of George Brent in "The Great Lie" (1941).
As middle age approached, Astor moved gracefully into a third stage of work in mother roles, usually sympathetic, most famously as Judy Garland's mom in the warm Technicolor musical, "Meet Me In St. Louis" (1944). Her striking supporting cameo as a prostitute in "Act of Violence" (1949) and her domineering mother in "Stranger in My Arms" (1959) were but two of the fine performances she was to give through the early 1960s. She also penned a number of novels and two well-received, intelligent memoirs.