His father was English-born Robert Stanley 'Tan' Wilcoxon, manager of the Colonial Bank in Jamaica[3] and his mother, Lurline Mignonette Nunes, was a Jamaican amateur theatre actress, descendant of a wealthy Spanish merchant family.

But because the grandmother was too frail to care for the children, they were first sent to a bad foster home, where they became ill from malnutrition and neglect until this was discovered by the authorities, and they were moved to an orphanage.

"[2] Among these roles, he found critical success playing Captain Cook in a production of Rudolph Besier's The Barretts of Wimpole Street at the London Queen's Theatre alongside Gwen Ffrangcon-Davies, Scott Sunderland and Cedric Hardwicke.

[2] In June 1932, at the Queen's Theatre, he played Donald Gage alongside Edith Evans as Irela in Sir Barry Jackson's production of Beverley Nichols' novel Evensong.

[2] In 1932, he appeared in a remake of the 1929 film The Flying Squad (based on the novel by Edgar Wallace), reprising the role originated by future-Hitchcock regular John Longden.

Also in 1933, "while acting on stage in Eight Bells, a talent scout for Paramount Pictures reportedly arranged a screen test which came to the attention of producer-director Cecil B. DeMille in Hollywood.

"[2] DeMille recalls in his autobiography: One of my longest and closest professional and personal associations began because I was impatient about waiting my turn for the use of a projection room at the studio, while I was casting Cleopatra.

While waiting in the booth, I heard, come from the soundtrack of the test film [being shown], a resonant, manly voice, with only a pleasant trace of an English accent...

[2] After the lack of success of The Crusades, Wilcoxon's career stalled; although he featured—and starred—in a number of films, most were "minor B's like The President's Mystery and Prison Nurse for Republic [Pictures].

"[2] Wilcoxon himself deemed his worst acting job to be in Mysterious Mr. Moto (1938), in which year he played in If I Were King and featured in Five of a Kind with the Dionne quintuplets.

[2] Wilcoxon, in his role as the vicar, "wrote and re-wrote" the key sermon with director William Wyler "the night before the sequence was to be shot.

"[2] The speech "made such an impact that it was used in essence by President Roosevelt as a morale builder and part of it was the basis for leaflets printed in various languages and dropped over enemy and occupied territory.

"[2] Upon his return from war service, Wilcoxon "picked up his relationship with Cecil B. DeMille" with Unconquered, and after starring as Sir Lancelot in the 1949 musical version of Mark Twain's A Connecticut Yankee in King Arthur's Court (with Bing Crosby in the title role), he featured (with "fifth starring billing") in DeMille's Samson and Delilah (1949).

In the late 1940s, "several young actors and actresses came to Wilcoxon and wife Joan Woodbury and asked them to form a play-reading group", which began to take shape as the 'Wilcoxon Players' in 1951, when the two "transformed their living room into a stage.

"[13] In the last two decades of his life, Wilcoxon worked sporadically and accepted minor acting roles in a number of television and film productions.

[14] Through loans from the assets he acquired from his early acting career, Wilcoxon assisted his brother Owen in establishing himself in 1931 as a partner in the Vale Motor Company in London.

[15] English-born actress Heather Angel, whom he had previously acted with in Self Made Lady (1932) when they were both in England, had come to Hollywood a few months before Wilcoxon and met him again in 1934.