Armand Douglas Hammer was born in Los Angeles, California, to Dru Ann Mobley and Michael Armand Hammer, a businessman. His great-grandfather, Armand Hammer, was a prominent tycoon and philanthropist who ran Occidental Petroleum for many decades. Hammer's ancestry includes Russian-Jewish, English, Scots-Irish, and German.
He has a younger brother, Viktor Hammer, who shares the same first names as their great-grandfather and his brother. His parents are involved in various charitable organizations, with his father serving as chairman and CEO of the Armand Hammer Foundation, and his mother as a board member.
Hammer's family moved to Dallas, Texas, when he was approaching school age, and later to the Cayman Islands in 1993, where they stayed for five years. He attended the Grace Christian Academy, a school his father set up, before returning to Los Angeles at the age of 13.
Hammer made his stage debut at a young age and left school in the 11th grade to pursue acting. He took courses at Pasadena City College and UCLA to continue his education. He had various small roles before being cast in Billy: The Early Years (2008) and later gained recognition for his dual role as the Winklevoss Twins in The Social Network (2010).
Hammer has since appeared in a range of films, including J. Edgar (2011),Mirror Mirror (2012),The Lone Ranger (2013),The Man from U.N.C.L.E. (2015),The Birth of a Nation (2016),Nocturnal Animals (2016),Mine (2016),Free Fire (2016),Cars 3 (2017),Call Me by Your Name (2017),Hotel Mumbai (2018),On the Basis of Sex (2018),Wounds (2019),and Rebecca (2020).
In his personal life, Hammer was married to Elizabeth Chambers from 2010 to 2020 and has two children with her.
