Before becoming a Mythbuster, Grant Imahara was an animatronics engineer and modelmaker for George Lucas' Industrial Light & Magic in Marin County, California. He specialized in electronics and radio control at the ILM Model Shop, and has credits on numerous movies, including Jurassic Park: The Lost World, Star Wars: Episode I - The Phantom Menace, Galaxy Quest, AI: Artificial Intelligence, Star Wars: Episode II - Attack of the Clones, Terminator 3: Rise of the Machines, Matrix: Reloaded and Revolutions, and most recently, Van Helsing and Star Wars: Episode III.

He has installed electronics in R2-D2 units for Star Wars Episodes I and II, replacing the halogen light source and rotating color wheel (for the sparkly lights) with a custom microcontroller-based LED circuit that was originally created to make the pulsating lights for the main engines of the Protector, from Galaxy Quest. He also upgraded all of the radio equipment and speed controls to modern standards. Along with R2-D2 Crew Chief Don Bies and Nelson Hall, he is one of only three official R2-D2 operators in the United States.

Grant developed a custom circuit to cycle the Energizer Bunny's arm beats and ears at a constant rate. He performed all electronics installation and radio programming on the current generation of Bunnies. He later became the Bunny's driver and the Crew Supervisor on numerous commercials in Los Angeles, Vancouver, Mexico, and New Zealand.

Grant has a Bachelor of Science degree in Electrical Engineering from the University of Southern California. He picked up his mechanical skills from the machinists at the ILM Model Shop, many of whom date back to Howard the Duck (1986).

For fun, Grant has competed in Comedy Central’s BattleBots with his robot "Deadblow," which he designed and built. Deadblow won two Middleweight Rumbles and was the Middleweight runner-up in 2000. It set a record for most number of hits in the first season of the show, and was ranked number on in Season 3.0.

In 2003, Wiley Technology Publishing released Grant’s book Kickin’ Bot: An Illustrated Guide to Building Combat Robots. At 528 pages long, it is regarded by many combat robot-building enthusiasts as the “bible” for that sport. It has a five-star average customer review on Amazon.com.

Grant appeared on TLC’s Junkyard Wars in a two-hour special called “Junkyard Wars Goes to the Movies” as the captain of Team ILM. They created a 13-foot tall R2-D2 out of junk in 20 hours that was equipped with a flamethrower, hydraulic lifting arm and CO2 pneumatic projectile gun. Team ILM won the competition, which challenged the junkyard machines to destroy a fleet of attacking aliens with their various weapons.

Grant’s skill set includes electronics design and fabrication, machining, welding, woodworking, CAD layout, pneumatics, CNC programming, and laser cutting, as well as some moldmaking and paint.