Hadad is of Lebanese background. The right-hander turned pro in 1988 and reached his highest individual ranking on the ATP Tour on September 11, 1995, when he became World No. 78. His best performance at a Grand Slam came at the 1996 Australian Open and the 1995 U.S. Open where he made it to the third round.
Hadad participated in 20 Davis Cup ties for Colombia from 1989-2001, posting a 23-5 record in singles and a 12-6 record in doubles.