Nelson was born in Portland, Maine, the son of Merle (née Royte), a court mediator and former member of the Maine state legislature, and Leonard Nelson, a corporate lawyer. His family is Jewish, and his father was the first Jewish president of the Portland Symphony Orchestra. He has two sisters, Eve and Julie. He went to school at St. Paul\'s School in Concord, New Hampshire and Waynflete School in Portland, Maine, and studied at Haverford College in Pennsylvania, leaving during his sophomore year. He subsequently moved to Manhattan to study acting with Stella Adler.\n', '
Nelson began acting in the mid-1980s, starring in Making the Grade (1984), and in Fandango (1985) opposite Kevin Costner. It was his roles in John Hughes\'s The Breakfast Club (1985) and Joel Schumacher\'s St. Elmo\'s Fire (1985) - and his affiliation with the Brat Pack - that made Nelson a star (along with Emilio Estevez, Anthony Michael Hall, Rob Lowe, Andrew McCarthy, Demi Moore, Molly Ringwald, and Ally Sheedy). The St. Elmo\'s Fire (Man in Motion) music video - also directed by Schumacher - reached No. 1 in the US (1985), and was written by David Foster and John Parr and performed by John Parr; Nelson appears in the video. A subsequent article in New York magazine, which focused primarily on the success of these films, resulted in the term "Brat Pack" being coined.\n', '
In 1986 Nelson provided the voice of Hot Rod/Rodimus Prime in The Transformers: The Movie and teamed up with Breakfast Club alumna Ally Sheedy for a third time in Blue City. He also provided narration for Bill Couturie\'s Dear America: Letters Home from Vietnam, a critically acclaimed war documentary that featured a cast including Tom Berenger, Robert De Niro, Willem Dafoe, and Matt Dillon. Film critic Roger Ebert praised the documentary, and it maintains a 100% rating on Rotten Tomatoes. He starred opposite Burt Reynolds in the ABC Afterschool Special Shattered If Your Kid\'s On Drugs, which also featured Megan Follows and Dermot Mulroney. In 1987 he starred in the Bob Clark courtroom comedy From the Hip, which co-starred John Hurt and Elizabeth Perkins; he also provided a stand-out performance in Billionaire Boys Club, a courtroom thriller based on actual events; his performance earned him a Golden Globe Award nomination for Best Actor in a Mini-Series. In late 1988 he played Konstantin in Chekhov\'s The Seagull directed by Charles Marowitz at the Los Angeles Theatre Center, earning praise, as did the entire production. Nelson closed the 1980s with the William Lustig thriller, Relentless (1989), in which he plays a Los Angeles serial killer being hunted by two police officers (Robert Loggia and Leo Rossi); he provided a cameo in the Adam Rifkin road film Never on Tuesday (1989) along with Nicolas Cage, Cary Elwes, Emilio Estevez and Charlie Sheen; and appeared in Tommy Chong\'s Far Out Man (1989) with Rae Dawn Chong and C. Thomas Howell.\n', '