Witsken played from 1983 to 1985 for the University of Southern California from 1983 to 1984 for the Junior Davis Cup team of the United States. In 1985 he became a professional tennis player. In the same year he stood at the side of Jorge Lozano, his partner from college times, in the quarterfinals of Indianapolis. The following year, he reached through a victory over Jimmy Connors surprisingly the second round of the U.S. Open, he also was in the semifinals of Scottsdale. His only singles final on the ATP World Tour, he reached in 1990 in San Francisco, but it lost to Andre Agassi. In the doubles competition, he could win twelve tracks, six of them with his longtime partner Lozano. A further nine times he stood in a double finals. Its highest listing in the tennis world ranking he reached in 1989 with position 43 in the singles and in 1988 with four position in the doubles.
His best individual result at a Grand Slam tournament was reaching the quarter- finals of the Australian Open 1988 In the same year he stood at the side of Jorge Lozano in the semifinals of the doubles competition of the U.S. Open. ; Moreover, he stood in a double quarter-finals of the Australian Open and the French Open. His second-round defeat by Greg Holmes at Wimbledon 1989 was the longest ever there discharged game with 5 hours and 28 minutes. Only in 2010 the record was broken in the record match between John Isner and Nicolas Mahut.
Witsken died of a brain tumor. He was married and had four children.