Other characters portrayed by Fox include Marty Jr. and Marlene McFly in Back to the Future Part II, Seamus McFly in Back to the Future Part III, and William Sean McFly in Back to the Future: The Game.
After having co-starred in a television series called Family Ties for a few years, series producer Gary David Goldberg was approached and asked to let Fox star in a Steven Spielberg produced film about a time-traveling teenager. At first, Goldberg did not inform Michael about the offer, not wanting to lose Michael to film stardom. Months later, Goldberg was again asked about Michael because Eric Stoltz, who had been chosen for the part after Goldberg stated that Fox was not available, was reportedly not giving the energetic performance that Robert Zemeckis, the director, was looking for. Goldberg finally told Michael about the offer and he quickly agreed to play the role of Marty McFly in the film Back to the Future. Fox would rehearse for Family Ties from 10:00 A.M. to 6:00 P.M. After he was done, he would be rushed to the Back to the Future set where he would rehearse and shoot until 2:30 A.M. This schedule lasted for two full months.
During the year 1985, Fox filmed the teen comedy film, Teen Wolf, before filming Back to the Future, but Back to the Future eventually was released a month before. On July 4, 1985, Back to the Future was number one at the box office. The film was number one for 11 consecutive weeks and eventually earned a worldwide total of $381.11 million. Soon after its release, Fox also appeared in commercials for Pepsi, which was featured in the film.
After Family Ties ended, he continued work on the Back to the Future trilogy with Part II and Part III. Prior to his work on the second and third films, Fox also engaged in some dramatic roles, such as Bright Lights Big City, where he plays an alcoholic journalist, and Casualties of War, where he played a US Army private fighting in Vietnam who witnesses his superiors kidnapping and raping a native woman and is conflicted how to handle it.
During the 1989 production of Back to the Future Part II, Fox's father passed away, and his wife, Tracy Pollan, gave birth to his first son. Fox, then 28 years old, was made to look "middle aged" with the assistance of makeup artist Bron Roylance, and he paid homage to his father by adding some of his mannerisms to the character. (On June 9, 2008, Fox turned 47 years old, the same age as Marty McFly in 2015.)
Fox was an animal rights activist and a vegetarian, which caused two scenes in the trilogy to be slightly adapted. At Marty McFly's future home in Part II, although Marty Jr. takes a slice of pepperoni pizza at dinner, he picks all the pepperoni off before eating it. At the McFly Farm in Part III, there is no meat on the fork he transfers from the serving dish to his plate, and then to his mouth, before he spits out several pieces of buckshot.After the release of Back to the Future Part III in May 1990, Fox started displaying symptoms of early-onset Parkinson's disease later the same year while shooting the movie Doc Hollywood, though he wasn't properly diagnosed until the following year. In 1998, he decided to go public with his condition, and since then he has been a strong advocate of Parkinson's disease research. In 2000, Fox semi-retired from acting.
Prior to his retiring, Michael J. Fox played Deputy Mayor Michael Flaherty in the sitcom Spin City and had that role from Seasons 1-4 (1996-1999), as well as reprising the role for several episodes of the final season during 2001. Christopher Lloyd appeared along with Michael during the Season 3 episode "Back to the Future: Judgement Day" as Mike's political mentor.
In an episode of Back to the Future: The Animated Series, Marty McFly believes he looks like Michael J. Fox, a sort of fourth wall breach or self-reference, however the voice of Marty in the series was not of Fox's, but instead David Kaufman.
In 2001, Fox voiced the protagonist Milo Thatch (who in the sequel was voiced by James Arnold Taylor) in the animated film Atlantis: The Lost Empire. In an interview promoting the film, Fox had considered more about voice acting as it was more liberal than on-screen acting, such as not requiring the entire cast and crew to be present at all times.
From 1999-2006, Fox provided the voice for the title character in Stuart Little, Stuart Little 2 and Stuart Little 3: Call of the Wild. Like with Marty McFly on Back to the Future: The Animated Series, David Kaufman would provide the voice for Stuart in the short lived cartoon. In the early 2000s, Fox played a doctor with obsessive-compulsive disorder on the comedy drama series Scrubs.
Michael J. Fox was unable to reprise his role for Back to the Future: The Game, with the role going to AJ LoCascio. He did, however, provide voice work on Back to the Future: The Game - Episode 5: OUTATIME (which include William McFly and 3 future dopplegangers of Marty).
As of 2013, Fox appeared as the lead in the sitcom The Michael J. Fox Show playing news anchor Mike Henry who originally took leave from his job due to Parkinson's disease, but recently went back to said job. The episode, "Health" (which only aired in Australia), featured an appearance by Lloyd as the boss of Michael's wife Annie.
- Fox, in reality, hasn't got a middle name that commences with the letter 'J'. His actual middle name is Andrew, as in Michael Andrew Fox. He chose to be billed as Michael J. Fox due to a rule in the Screen Actors Guild that no two actors can have the same or similar names, and a Michael Fox was already registered. Michael borrowed the middle 'J' from the middle name of Michael J. Pollard, who was one of Fox's favorite character actors. The reason he didn't want to be credited as Michael A. Fox was due to his Canadian heritage, which is often associated with peppering statements with "eh", and jokes would be "Michael, Eh? Fox". Another reason is that other jokes would be "Michael's a fox!"
- Though Fox didn't appear in it, archive footage of him from Family Ties was used in Mickey's 60th Birthday, which also included Charles Fleischer as Roger Rabbit, and Richard Dysart as Leland McKenzie.
- An in-joke to Fox's other acting was seen in Back to the Future Part II in the Cafe 80s, which showed multiple screens looping shows from the 1980s to include The A-Team, Airwolf, Mr. Belvedere, Disney's Adventures of the Gummi Bears, The Smurfs, and so forth. One screen shows Family Ties, which Fox was also well-known for, and another shows Taxi, Christopher Lloyd's well-known TV role.
- Michael J. Fox reprised the roles of Marty, Marty Jr, Marlene and Seamus McFly for the 2015 video game Lego Dimensions. The game creators stated that he was cast, because they wanted the characters to sound as authentic as possible. In that same year, he also reprised the role of Marty on the Jimmy Kimmel show, alongside Christopher Lloyd as Doc Brown, to celebrate Back to the Future Day.