Warden was born in Amersham, Buckinghamshire, he studied at Dr Challoner's Grammar School and received a B.A.
[1] He is probably best known for his appearances in the HBO miniseries Band of Brothers as 1st Lt. Harry Welsh, the BBC docudrama Dunkirk as Major Phillip Newman RAMC, the HBO/BBC Two historical drama, Rome, as Quintus Valerius Pompey and Channel 4's period drama Indian Summers as Ronnie Keane.
He performed in the BBC serial production, Apparitions, as the character Michael, who is possessed by a demon.
He played Mike Taylor, a police inspector, in the crime drama Happy Valley.
[4] In 2019, Warden appeared in the BBC One medical drama series Casualty as Ciaran Coulson.