Ayres is best remebered, though, for his role as a disillusioned German soldier in the Oscar-winning, 1930 classic All Quiet on the Western Front and for his real-life conflict with the military. He was shunned by movie studios and film-goers after declaring himself a conscientious objector during World War II, eventually volunteering as a medic and chaplain's aide, earning three battle stars and reviving his acting career.
Ayres' Hollywood career spanned seven decades. He made his major film debut opposite Greta Garbo in 1929's The Kiss. His most enduring screen role, Dr. James Kildare, began in 1938 with Young Dr. Kildare, the first of nine Kildare movies. In 1948, he garnered an Oscar nomination for Johnny Belinda. Ayres won a Golden Globe Award in 1976 as producer of Altars of the World, a documentary on world faiths.
During the 1970s and '80s, Ayres appeared mostly in TV series (The Mary Tyler Moore Show, Highway to Heaven) and grade-B movies (Battle for the Planet of the Apes, Damien: Omen II). His final appearance was in the 1994 TV movie Hart to Hart: Crimes of the Hart.
Ayres was married to actress Lola Lane from 1931 to 1933, and to Ginger Rogers from 1934 to 1941. He is survived by his third wife, Diana Hall, whom he married in 1964, and their son, Justin.