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Michael J. Fox – Marty McFly
THEN: Fox played the film's time-traveling protagonsit Marty McFly in the Back to the Future franchise, coming in to replace Eric Stoltz after Stoltz had been shooting for several weeks on the film. Fox was the original first choice for Marty but had to initially drop out due to other commitments.
NOW: Fox most recently starred in the NBC sitcom The Michael J. Fox Show but has appeared in a number of roles as both himself and other characters over the years. He also lent his voice to Telltale Games' Back to the Future: The Game.
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Christopher Lloyd – Emmett Brown
THEN: Lloyd played the kooky Emmett "Doc" Brown, whose cry of "1.21 gigawatts" remains one of the film's most iconic lines. The impetus for Marty's adventures, it would be difficult to separate Doc Brown from the love of Back to the Future that has remained in the decades since its release.
NOW: Lloyd has steadily continued working in film and television since Back to the Future, and has reprised his Doc Brown role several times. Most recently, he's lent his voice to the upcoming video game Lego Dimensions as Doc Brown, even appearing in a recent trailer for the game in character.
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Lea Thompson – Lorraine Baines-McFly
THEN: Thompson played Marty McFly's mother, Lorraine, who unknowingly develops a crush on her own son when he travels back in time, pretending to be a man named "Calvin Klein."
NOW: Thompson recently played herself in an episode of NBC's canceled sitcom A to Z, which included a nod to the franchise's hoverboard. But in the years since, she has starred in a number of films and shows, including a series regular role on ABC Family's Switched at Birth.
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Crispin Glover – George McFly
THEN: Glover played Marty's father George, who -- with Marty's help -- begins a relationship with Lorraine (to ensure Marty actually exists in the future).
NOW: Jeffrey Weissman replaced Glover in the Future sequels, and though he's acted in mainstream films periodically since the original BTTF (notably in Hot Tub Time Machine), Glover has moved into several other fields during his career. Glover began to release music in the late '80s and also started a company, Volcanic Eruptions, which serves as a paltform for Glover to release movies he's written and produce films.
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Tom Wilson – Biff Tannen
THEN: Wilson played Biff Tannen, the bully who picked on George McFly and became a major obstacle as Marty attempted to unite his parents.
NOW: Wilson appeared in the sequels as Biff, as well as other members of the Tannen family. But since then, aside from acting, he's hosted his own podcast, continued a stand-up comedy career, and done voiceover work for film, television, and video games. He's also become known for "Biff's Question Song" and his business card, which answer all of the most frequently asked questions he's been asked over the years about Back to the Future.
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Claudia Wells – Jennifer Parker
THEN: Wells played Marty McFly's girlfriend, Jennifer Parker, who appears in scenes that bookend the original Back to the Future.
NOW: Parker was replaced in subsequent sequels by Elisabeth Shue, though she did reprise her role in the Back to the Future video game in 2011. She otherwise took an extended leave from acting but currently has several projects lined up, including the horror film Room and Board.
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James Tolkan – Mr. Strickland
THEN: Tolkan played Gerald Strickland, who worked at Hill Valley High School and, in both 1955 and 1985, was a thorn in the side of the McFlys. An authoritarian at Hill Valley, Strickland lived a life with the sole purpose of whipping as many "slackers" into shape as he could.
NOW: Tolkan has appeared in a number of television series since his time in Back to the Future. Most recently, he was seen in HBO's Phil Spector and is set to star in Bone Tomahawk.
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Marc McClure – Dave McFly
THEN: Back to the Future may showcase Marty McFly's quest to make sure his parents meet and fall in love, but he wasn't the only McFly kid whose existence was at risk. McClure played the oldest McFly child Dave. He, along with Wendie Jo Sperber (who died in 2005) as Linda, rounded out the McFly clan.
NOW: McClure has popped up in a number of guest starring roles throughout the years on television shows like Nash Bridges, Smallville, and The Shield. His most recent prominent project was 2008's Frost/Nixon.