Silverheels was born Harold Jay Smith in Canada, on the Six Nations of the Grand River reserve, near Hagersville, Ontario.

While playing in Los Angeles on a touring box lacrosse team in 1937, Silverheels impressed Joe E. Brown with his athleticism.

[a] From the late 1940s, he played in major films, including Captain from Castile starring Tyrone Power (1947), Key Largo with Humphrey Bogart (1948), Lust for Gold with Glenn Ford (1949), Broken Arrow (1950) with James Stewart, War Arrow (1953) with Maureen O'Hara, Jeff Chandler and Noah Beery Jr., The Black Dakotas (1954) as Black Buffalo, Drums Across the River (1954), Walk the Proud Land (1956) with Audie Murphy and Anne Bancroft, Alias Jesse James (1959) with Bob Hope, and Indian Paint (1964) with Johnny Crawford.

On January 6, 1960, he portrayed a Native American firefighter trying to extinguish a forest fire in the episode "Leap of Life" in the syndicated series, Rescue 8, starring Jim Davis and fellow Canadian Lang Jeffries.

[16] He also began to publish poetry inspired by his youth on the Six Nations Indian Reserve and recited his work on television.

In 1966, he guest-starred as John Tallgrass in the short-lived ABC comedy/Western series The Rounders, with Ron Hayes, Patrick Wayne, and Chill Wills.

In 1969, he appeared as Tonto without the Lone Ranger in a comedy sketch on The Tonight Show Starring Johnny Carson.

In 1970, he appeared in a commercial for Chevrolet as a Native American chief who rescues two lost hunters, who had ignored his advice, in that year's Chevy Blazer.

Silverheels spoofed his Tonto character, opposite Clayton Moore, in a Stan Freberg Jeno's Pizza Rolls TV commercial, which was set to the music of Gioachino Rossini's 'William Tell Overture," and in The Phynx, opposite John Hart, both having played the Lone Ranger in the original television series.

"[22] Married twice, Silverheels had two sons (Steve, with his first wife; Jay Anthony Jr., who followed his father into acting) and four daughters (Marilyn, Gail, Pamela, and Karen).

A fictionalized version of Silverheels appears in the Thrilling Adventure Hour serialized segment "Tales from the Black Lagoon".