James Andrew Eric Phelps was born on February 25, 1986, in Sutton Coldfield, Birmingham, England. He is the twin brother of Oliver Phelps, who was born thirteen minutes earlier. In 2000, the twins skipped class to audition for the Harry Potter films. After approximately six rounds of auditions, both brothers were cast. James received on-set tutoring throughout the decade-long production, juggling school and a global franchise simultaneously.

James played Fred Weasley across all eight Harry Potter films from 2001 to 2011. He and Oliver also appeared in the HBO Max special Harry Potter 20th Anniversary: Return to Hogwarts (2022) and have remained closely tied to the franchise through conventions and events. In 2025, the twins participated in the grand opening of Universal Epic Universe at Universal Orlando Resort in Florida, helping unveil The Wizarding World of Harry Potter — Ministry of Magic themed land.

Beyond Harry Potter, James co-created the Normal Not Normal podcast with Oliver (Season 3, 2021), interviewing celebrities about fame and personal growth. In 2024, the twins debuted as co-hosts of Harry Potter: Wizards of Baking on Food Network, a baking competition series inspired by the Wizarding World, which returned for a second season in 2025.