James Marsden is an actor who began his career with a role on the pilot episode of The Nanny (1993) as Eddie. He then became part of the Canadian television series Boogies Diner (1994), which aired for one season. After that series ended, he got a brief role as the original Griffin on Fox's Party of Five (1994). His first big break came when he became the lead on the short-lived ABC series Second Noah (1996). In 1996, he attended an audition for a movie titled Primal Fear (1996) but lost that role to Edward Norton. Two years later, he was offered a lead role in 54 (1998), which he turned down.

James' star power increased when he starred in David Nutter's Disturbing Behavior (1998), alongside Katie Holmes and Nick Stahl, which had mixed reviews, but mostly positive ones. His role in the television series as Glenn Foy in Ally McBeal (1997) is one of his biggest achievements to date. He became one of the main cast members during the first half of season 5, where he showcased his singing abilities. The 5' 10" star later played Lon Hammon Jr. in the romantic movie The Notebook (2004), based on a novel by Nicholas Sparks. His movies The Alibi (2006) and 10th & Wolf (2006) were also released around the world in 2006. One of his most memorable roles to fans is his role as Cyclops in the X-Men (2000) movie franchise. He was among the actors who starred in all three of the X-Men movies, working alongside Patrick Stewart, Famke Janssen and Hugh Jackman. He had to wear lifts for most of his scenes in the X-Men movies, because his character Cyclops is supposed to be 6' 3" compared to a 5' 3" Wolverine.

In 2006, he played Richard White in Superman Returns (2006), directed by Bryan Singer. In 2007, James played Corny Collins in the film Hairspray (2007), an adaptation of the Broadway musical based on John Waters' movie Hairspray (1988). He joined a star-studded cast including John Travolta, Queen Latifah and Michelle Pfeiffer. James not only acted in that movie but also sang two of the film's songs, "The Nicest Kids In Town" and "Hairspray". His next role was in the Disney movie Enchanted (2007), playing Prince Edward, alongside Amy Adams, Susan Sarandon and Patrick Dempsey. He sang in two songs from the movie, "True Love's Kiss" and "That's Amore". Following his success in 2006 and 2007, James played the male lead role in the romantic comedy 27 Dresses (2008), opposite actress Katherine Heigl. The movie did well at the box office, earning a gross revenue of over $159 million.

Marsden played the male lead in the horror film The Box (2009), based on the 1970 short story "Button, Button" by author Richard Matheson. He starred opposite Cameron Diaz in the movie.

He co-starred in Accidental Love (2015), a politically-themed romantic comedy directed by David O. Russell and filmed in Columbia, South Carolina. Marsden's recent film roles include the sequel comedy Anchorman 2: The Legend Continues (2013), the romantic drama The Best of Me (2014), and the comedy Unfinished Business (2015).

James mentioned that despite all the attention he's getting from the public eye, he tries to keep himself as grounded as possible. He even admits that he flies coach instead of first class while traveling. In an interview he mentioned that he believes he has a certain responsibility to let his children know that he isn't special because of what he does, but who he is as a person.