Daniels wore the suit and provided the voice for the character in the original films and in a guest appearance on The Muppet Show. He has also supplied the droid's voice in spin-off audio dramas, video games, and animated series. Other credits include appearances on Young Indiana Jones.
- "I was such a fan of the Muppets that I had to suppress my uncool excitement when I arrived at the studio - didn't want to look like a deranged fan. I think they guessed anyway. I'd always loved the characters and the scripts were just off-the-wall enough to be outstanding. ... It was one of the most disciplined shows I ever did. Each member of the cast was a perfectionist who respected the needs and performances of the other cast members - a really professional group led by Jim. I think his weird imagination spurred everyone on, and he surrounded himself with talented and dedicated artists."
In the same interview, Daniels makes mention of the "slight danger" involved in filming the show. The C-3PO suit provides the performer inside with limited vision. At the same time, all of the actors appearing with the Muppets worked on elevated sets. "It would have been all too easy to fall into the pit at my feet." Always the humorist, he added, "I'm sure Frank would have made a soft landing, but Piggy would not have been amused."
Daniels also mentioned that he received a "Silver Kermit" as a gift, over dinner at Julie's during the filming of his episode.
Daniels was born in Salisbury, Wiltshire, England, the son of a plastics company executive. Never a science fiction fan, Daniels has said that before his role in Star Wars, the only science fiction film he had ever gone to see in a theatre was 2001: A Space Odyssey in 1968. He was so dissatisfied with the film that he walked out after only ten minutes and demanded his money back.
Daniels has played C-3PO in all six of the Star Wars feature films, as both the body and voice of the golden protocol droid. In Star Wars Episode I: The Phantom Menace, he wore a blue Spandex costume so that during editing of the movie his body could be turned into many different wires and circuits. Daniels has reprised the role for various promotional work such as hosting The Making of Star Wars, Star Wars Connections and The Science of Star Wars; for appearances on The Muppet Show and Sesame Street and an anti-smoking public service announcement; for The Star Wars Holiday Special; in advertising for Star Wars licensed products such as Kenner toys and even a breakfast cereal based on the character.
Daniels voiced C-3PO in the Star Wars radio serial based on the original trilogy. He is the only cast member of the original Star Wars trilogy to voice his character in all three parts of NPR's dramatizations of the trilogy. He voiced C-3PO for three animated series: Droids, Star Wars: Clone Wars, and Star Wars: The Clone Wars. Other C-3PO voicework by Daniels includes: the Christmas-themed Christmas in the Stars album, the multiple Walt Disney theme park attractions, Star Tours and Star Tours: The Adventures Continue, the fan film/show Raiders of the Lost Jedi Temple of Doom: A Fan Film of Epic Proportions, and the Star Tours shutdown ceremony as a part of the Disney's Hollywood Studios' "Last Tour to Endor" event at Star Wars Celebration V in Orlando, Florida. He also provided the narration and all character voices for the audio books Dark Force Rising and The Last Command.
He contributed the foreword to the collected scripts of the Return of the Jedi radio drama, as their author Brian Daley died just as the episodes were being recorded. Daniels' other Star Wars-related writings include the Wonder Column for Star Wars Insider magazine and a comic book adventure for C-3PO and R2-D2 entitled The Protocol Offensive, published by Dark Horse Comics.
He controlled the puppet for 2002's Star Wars: Episode II: Attack of the Clones, but all these scenes were cut, with the droid's first appearance in the film being Daniels in costume. In this film and 2005's Star Wars: Episode III: Revenge of the Sith, he also performed the vocal tracks for scenes that featured a computer-generated C-3PO. Daniels is the only actor to act in the original six films, the 2008 Clone Wars film, and the related television series. Daniels hosted the Star Wars: In Concert North American tour.
Daniels also makes cameo appearances as a humanoid in two scenes of the feature films. His character, Lieutenant Dannl Faytonni, is named as a tribute to his own name, albeit in modified form. The character appears in the Outlander nightclub scene early in Star Wars Episode II: Attack of the Clones as a man in blue uniform who can be seen in a cutaway reaction shot after Obi-Wan disarms the bounty hunter Zam Wesell. Faytonni can also be seen at the Galaxies Opera House in Star Wars Episode III: Revenge of the Sith.
He returns for Star Wars Episode VII: The Force Awakens, Rogue One, Star Wars Episode VIII: The Last Jedi, Ralph Breaks the Internet, and Star Wars Episode IX: The Rise of Skywalker. He also played Tak in Solo.