Now using the stage name Jack Lord, he was cast as Elizabeth Montgomery's doomed husband in "The Court Martial of Billy Mitchell" (1955), then appeared as Robert Taylor's financially-strapped war buddy in "Tip on a Dead Jockey" (1957). In "God's Little Acre" (1958), Lord joined Vic Morrow as Robert Ryan's treasure-seeking sons. That same year, he had his first real leading role in "The True Story of Lynn Stuart", but it was really Betsy Palmer's picture; Lord was merely the drug-selling thug she uses in her quest for revenge.
With movie stardom proving elusive, Lord turned to television, where he had been making guest appearances since 1956, often cast as villains in Westerns. His first regular series role was as the champion rodeo rider "Stoney Burke" (ABC, 1962-63) Five years later, the actor landed a second series, "Hawaii Five-O", about state police working directly for the governor. Lord jumped at the chance and also signed on as producer of the series, which was shot entirely in Hawaii. Although hardly an award-winner, and said to be disliked by CBS founder William S Paley, the police show was a huge ratings success and made Lord a TV star. His catchphrase to sidekick James MacArthur, "Book 'em, Danno!", entered into TV history. Lord attempted to produce additional series from Hawaii, but none of the pilots sold.
After "Hawaii Five-O" ran its course, Lord virtually retired form acting to concentrate on a career as an artist. His paintings not only sold for high amounts, but also hang in more than 40 museums worldwide, including the Metropolitan Museum of Art, the Whitney Museum and the Brooklyn Museum of Art in New York, the Biblioteque Nationale in Paris, and the Library of Congress.