Natalia Elsie Warner was born on 5 September 1991 in Bath, Somerset. She is of Russian descent. She grew up in Chippenham, Wiltshire, where she studied at Hardenhuish School. She later enrolled at The Royal High, an all girls boarding school. At age 16, she transferred to King Edward's, where she began acting in the senior school plays. Performing the roles of Puck in A Midsummer Night's Dream, Abigail in The Crucible, and Edward in Edward Scissorhands, Warner was inspired to become a member of the Bristol Old Vic Youth Theatre, where she continued to perform and was soon scouted by a talent agent.

Warner made her film debut in Richard Ayoade's dystopian thriller The Double, which received a positive review from Empire. She stars as the female lead in Shoreline Entertainment's romantic drama Learning to Breathe (Official Selection at the 2016 London Raindance Film Festival), and British comedy The Five Wives and Lives of Melvyn Pfferberg, an Official Selection at the 2016 LA Shorts Fest. Warner made her American film debut in Temple, a psychological thriller set in Japan, from David Lynch's production company Absurda.