Marty McFly

In 1985, Marty helps Doc with the DeLorean and ends up alone in 1955. He saves his father, George, from a car and accidentally makes his mother, Lorraine, fall for him. With the 1955 Doc's help, he tries to bring the two together at the school dance, plays guitar onstage and returns to 1985 on the clock tower lightning. The family he finds is very different from the one he left.

Doc takes Marty and Jennifer to 2015. Marty poses as his son, takes on Griff Tannen in a hoverboard chase and buys a sports almanac covering 1950 to 2000. Back home, he finds a Hill Valley ruled by Biff. In 1955 he relives the school dance unseen, recovers the book and burns it. Lightning sends Doc to 1885 and leaves Marty stranded in 1955.

With the 1955 Doc, Marty repairs the DeLorean and goes to 1885 to save his friend. He uses the name Clint Eastwood, faces Buford Tannen and escapes a lynching. In the duel, he uses a stove door as a vest. When he returns, he turns down a street race and, without knowing it, avoids the accident Doc warned about.

Michael J. Fox was the writers' first choice, but Eric Stoltz started shooting in the role. Per Wikipedia, the name Marty comes from a Used Cars production assistant, Marty Casella, and Zemeckis suggested McFly because it sounded All-American.