Martin Seamus "Marty" McFly, Sr. is the main protagonist in the Back to the Future film trilogy, and is portrayed by actor Michael J. Fox. Marty was also the main protagonist in the animated series where he was voiced by David Kaufman. In the videogame by Telltale Games, he is voiced by AJ LoCascio.
Marty was born in Hill Valley, California in 1968 to a family of Irish descent. Little is known about Marty's life prior to the first Back to the Future film, except for the fact that he accidentally set his parents' living room rug on fire when he was 8 (which we know from a statement of Marty's to his future parents).
In 1985, Marty plays lead guitar with his group The Pinheads and likes listening to Huey Lewis and the News, Tom Petty and the Heartbreakers, and Van Halen. He is also a talented skateboarder and proven to be an excellent shot with a gun, honed by endlessly playing shooting games such as Wild Gunman at his local 7-Eleven.
Although Marty is often accident prone and sometimes thought to lack critical thinking skills, he is nevertheless brave in the face of danger and can be very resourceful and clever. He has shown some good and basic street fighting skills in the movies. He often throws punches in hand-to-hand confrontations. His major character flaw is his pride, which causes him to take unnecessary risks to show others that he is not chicken, as demonstrated throughout various points throughout the trilogy. However, in the third film, when his ancestor Seamus McFly points out that Seamus's brother, Martin, was killed in an argument where someone questioned his bravery, Marty began to re-think his stance on what other people thought of him. This was highlighted when Marty refused to race Needles, despite Needles goading him into a race, thus avoiding the "automobile accident" involving the Rolls Royce, therefore changing his future for the better.
Source: Wikipedia, "Marty mcfly", available under the CC-BY-SA License.