John Jefferies

John Daniel Jefferies, Sr., often credited simply as John Jefferies, was a set designer on Star Trek: The Original Series and brother of Philip and Matt Jefferies. John Jefferies shared credit with Matt for designing the original phaser pistol. John Jefferies also worked on the final construction design for the USS Enterprise (NCC-1701).

Jefferies was born in Richmond, Virginia and grew up in New Jersey. He began his career in Hollywood following a stint in the United States Air Force. His first project was the 1966 film The Chase, whose cast included Paul Williams. Jefferies' subsequent film work included the 1967 classic Guess Who's Coming to Dinner and the musicals Funny Girl (on which Dick Rubin was property master) and Hello, Dolly! (with set dressings by Craig Binkley).

Both John and Matt Jefferies work on the 1967 Walt Disney film The Happiest Millionaire. John later worked as a set designer on the 1970 film Catch-22 while Philip Jefferies was the film's art director. During production, Philip became ill and was replaced by Matt. John also took over some of Philip's responsibilities on the film. On Catch-22, all three brothers were working under production designer Harold Michelson, who later headed the art department on.

From the 1970s until 2001, Jefferies was an art director and production designer on such television shows as Baa Baa Black Sheep (on which John Larroquette and James Whitmore, Jr. were regulars), The Greatest American Hero, Hardcastle and McCormick (starring Brian Keith and Daniel Hugh Kelly), Matlock, and JAG. In his later career, he was also a set designer on such films as BASEketball, I Still Know What You Did Last Summer, and Austin Powers: The Spy Who Shagged Me. He was also the art director on the 2001 film Just Visiting, which featured Malcolm McDowell.

Jefferies' daughter married the son of film editor Bruce Schoengarth.

John Jefferies at one time served as president of the International Alliance of Theatrical Stage Employes (IATSE) Set Designers and Model Makers. Jefferies died on 25 March 2010 due to complications from lung cancer. He was 74 years old.