Title: Back to the Future (TV series)
Content:  Thomas F. Wilson (Biff Tannen) voiced their characters from the films. Christopher Lloyd played Doc Brown in the live-action segments which opened and closed each episode while Dan Castellaneta provided the animated Doc Brown's voice. James Tolkan, who previously portrayed Principal Strickland from the films, voiced an unnamed Civil Defense Warden in the episode: "Marty Mcfly PFC". In addition, Bill Nye appeared as Dr. Brown's Lab Assistant during the live-action segments at the end of each episode performing scientific experiments related to the episode. Nye also serves as the show's technical advisor. These segments later led to Nye getting his own show.
Title: Back to the Future
Content: Michael J. Fox as Marty McFly: Christopher Lloyd as Emmett "Doc" Brown: Lea Thompson as Lorraine Baines-McFly: Crispin Glover as George McFly: Thomas F. Wilson as Biff Tannen: A high school student and aspiring musician An eccentric scientist experimenting with time travel A 1955 teenager who grows into Marty's unhappy, alcoholic mother A nerdy 1955 high schooler who grows into Marty's cowardly, submissive father A 1955 high school bully turned George's 1985 boss James Tolkan portrays Hill Valley high school principal Strickland in both 1955 and 1985. Back to the Future features a 1985-era cast that includes Claudia Wells as Marty's girlfriend Jennifer Parker, and Marc McClure and Wendie Jo Sperber as Marty's siblings Dave McFly and Linda McFly respectively. 
Title: List of Back to the Future characters
Content:  Jules Eratosthenes Brown and Verne Newton Brown (portrayed by Todd Cameron Brown and Dannel Evans in Back to the Future Part III and voiced by Josh Keaton and Troy Davidson in the animated series) are the two children of Doc Brown and his wife, Clara, who named them after their favorite author Jules Verne. The characters had minor, non-speaking roles in Back to the Future Part III but were further developed in the animated series. Jules, an introvert, mostly imitates his father's interests and mannerisms while Verne appears to be more outgoing and extroverted. Several plot points of the animated series revolve around either Jules or Verne altering history and the steps necessary to correct the damage. In the Back to the Future game when asked about his family, Doc reveals that his sons are now teenagers and their parents are discussing what time period they should attend college at.
Title: List of Back to the Future characters
Content:  Einstein (portrayed by Tiger and stuntman Dick Butler in the first film and Freddie in the other two and voiced by Danny Mann in the animated series) is Doc Brown's pet Catalan sheepdog. He later becomes one of the main characters in the animated series as the Brown family's dog. In the first film, Doc successfully tests his time machine by placing Einstein in it and sending him one minute into the future. In the animated series, Einstein becomes anthropomorphic and smarter, helping Doc with his inventions for traveling to the past and the future.
Title: Back to the Future Part III
Content: Michael J. Fox as Marty McFly / Seamus McFly ; Christopher Lloyd as Emmett "Doc" Brown ; Mary Steenburgen as Clara Clayton ; Thomas F. Wilson as Buford "Mad Dog" Tannen ; Lea Thompson as Maggie McFly ; James Tolkan as Marshal James Strickland ; Matt Clark as Chester the Bartender 
Title: List of Back to the Future characters
Content:  George Douglas McFly (portrayed by Crispin Glover in Back to the Future and by Jeffrey Weissman in Back to the Future Part II and Back to the Future Part III and voiced by Michael X. Sommers in Back to the Future: The Game) is married to Lorraine Baines McFly and is the father of Marty, Linda and Dave. Although he is one of the main characters in the first movie, George only makes cameos in Back to the Future Part II and Back to the Future Part III. In the first film, George is portrayed as weak and the main target of Biff Tannen's bullying. The novelization of the film expounds on George's history 
Title: Christopher Lloyd
Content:  Christopher Allen Lloyd (born October 22, 1938) is an American actor. He has appeared in many theater productions, films, and on television since 1961, and is known for portraying Dr. Emmett "Doc" Brown in the Back to the Future trilogy (1985–1990) and Jim Ignatowski in the comedy series Taxi (1978–1983), winning two Emmy Awards for the latter. Lloyd came to public attention in Northeastern theater productions during the 1960s and early 1970s, earning Drama Desk and Obie awards for his work. He made his cinematic debut in One Flew Over the Cuckoo's Nest (1975), and his television debut in The Adams Chronicles the following year. Lloyd also starred as Commander Kruge in Star Trek III: The Search for Spock (1984), Professor 
Title: List of Back to the Future characters
Content:  Doctor Emmett Lathrop "Doc" Brown is the inventor of the DeLorean time machine. At various points in time, Doc helps Marty restore the space-time continuum and reverse the changes that were caused by time travel. In 2008, the character was selected by film magazine Empire as one of The 100 Greatest Movie Characters of All Time, ranking at No. 20.
Title: Back to the Future: The Game
Content:  Back to the Future: The Game is an episodic graphic adventure based on the Back to the Future film franchise. The game was developed and published by Telltale Games as part of a licensing deal with Universal Pictures. Bob Gale, the co-creator, co-writer, and co-producer of the film trilogy, assisted Telltale in writing the game's story. Original actors Michael J. Fox and Christopher Lloyd allowed the developers to use their likenesses in the game for the lead characters Marty McFly and Doc Brown, respectively. Although Lloyd reprises his role as Doc, A.J. Locascio plays the role of Marty, while Fox later appeared to voice two cameo roles in the final episode, reprising his role as future versions of Marty McFly in addition to playing his forefather William. The game is split-up into 
Title: Back to the Future Part II
Content: Michael J. Fox as Marty McFly / Marty McFly Jr. / Marlene McFly ; Christopher Lloyd as Emmett "Doc" Brown ; Lea Thompson as Lorraine Baines-McFly ; Thomas F. Wilson as Biff Tannen / Griff Tannen / Gertrude Tannen ; Elisabeth Shue as Jennifer Parker ; James Tolkan as Mr. Strickland ; Jeffrey Weissman as George McFly ; Harry Waters Jr. as Marvin Berry ; Joe Flaherty as Western Union Man ; Charles Fleischer as Terry ; Flea as Douglas J. Needles  

Question: who plays the doc in back to the future?
Answer: Christopher Allen Lloyd.