Aline MacMahon was born on May 3, 1899, to William Marcus MacMahon and Jennie Simon MacMahon, a family of Scottish-Irish and Russian-Jewish ancestry.
She was educated at Erasmus Hall High School in Brooklyn and later attended Barnard College, graduating in 1920.
MacMahon began her career on stage, making her debut in "The Madras House" at the Neighborhood Playhouse Theater, and then appeared on Broadway in "The Mirage" in 1921.
She had a prolific career on Broadway, initially as a comedienne and impersonator, and later as a dramatic actress, impressing critics with her performances in plays such as "Beyond the Horizon" and "The Eve of St. Mark".
Her film career started in the 1930s, with roles in comedies like "Once in a Lifetime" and "Gold Diggers of 1933", as well as dramatic performances in films like "Silver Dollar" and "The Life of Jimmy Dolan".
MacMahon continued to work in film throughout the 1940s and 1950s, playing character parts and occasionally taking on meatier roles in films like "Dragon Seed" and "The Man from Laramie".
In the 1960s, she appeared in films like "Diamond Head" and "All the Way Home", before retiring from the screen in 1964.
MacMahon was married to Clarence S. Stern, and passed away in 1991 at the age of 92 due to pneumonia.
