Starred in the Broadway stage show "Drifting" (1922) that featured a
still wet-behind-the-ears Humphrey Bogart. Bogart remembered his kindness
during the play's run and 28 years later insisted on hiring Warwick to
play a juicy role in his film In a Lonely Place (1950).
Left his career on the Broadway stage when World War I broke out and enlisted in the US army. He spent 17 months in combat in France and returned to the US as a major.
In 1936 he was one of 24 actors given Actors Equity suspensions
for refusing to join the Screen Actors Guild.