Cornel Wilde was born Kornel Lajos Weisz on October 13, 1912 in Prievidza, Hungary (now part of Slovakia) to a Jewish family. In 1920, he immigrated to New York City with his parents, Rayna (Vid) and Vojtech Béla Weisz, and elder sister, Edith. His family Anglicized their names. Kornel took the name Cornelius Louis Wilde. He spent much of his youth traveling in Europe, developing a continental flair as well as an affinity for languages. He received a scholarship for medical school, but turned it down in favor of his new love, the theatre.

A natural athlete and a champion fencer with the U.S. Olympic fencing team, he quit the team just prior to the 1936 Berlin Olympics in order to take a role in a play. In 1937, he married Marjorie Heintzen (later known as Patricia Knight), and they both shaved a few years off their ages in order to get work, Wilde thereafter claiming publicly he was born in New York in 1915 while continuing to list his correct place and year of birth on government documents.

Shortening his name to Cornel Wilde for the stage, he appeared in the Broadway hit "Having a Wonderful Time", but it wasn't until he was hired in the dual capacities of fencing choreographer and actor (Tybalt) in Laurence Olivier's 1940 Broadway production of "Romeo and Juliet" that Hollywood spotted him. He played a few minor roles before leaping to fame and an Oscar nomination as Frederic Chopin in A Song to Remember (1945). He spent the balance of the 1940s in romantic, and often swashbuckling, leading roles.

During the 1950s, his star dimmed a little, and aside from an occasional blockbuster like The Greatest Show on Earth (1952), he settled mainly into adventure films. A growing interest in directing led him to form his own production company with the goal of directing his own films. Several of his ventures into film noir in this period, both his own and those of other directors, are quite interesting (The Big Combo (1955) and Storm Fear (1955), for example). He produced, directed and starred in The Naked Prey (1965), a tour-de-force adventure drama that brought him real acclaim as a director. His later films were of varying quality, and he ended his career in near-cameos in minor adventure films. He died of leukemia in 1989, three days after his 77th birthday, leaving behind an unpublished autobiography, "The Wilde Life".