Nelson studied philosophy at Haverford College in Pennsylvania. For acting, he came when he actually wanted to go with only one friend to an audition and won the audition. Then he moved to Manhattan and studied acting at the Stella Adler.
Right at the beginning of his career, he celebrated his greatest successes with John Hughes ' The Breakfast Club and Joel Schumacher's St. Elmo 's Fire - The passion burns deep. However, at this he could not reconnect, not only that his following films were commercially unsuccessful, he was also nominated twice for the Golden Raspberry as the worst actor. As a result, he also played partially in television movies before he got to the side of Brooke Shields in 1996 one of the main roles of the TV series Susan. Until 1999, he played in 76 episodes of the series.
Most recently, he was in direct-to- video films like The Day the Earth Stood Still 2 - Attack of the Robots, Bad Kids Go to Hell and be seen in guest roles on various series.