Seiden was a New York City schoolboy star at Jamaica High School, leading his team to the PSAL title in 1955 as a senior.[1] He chose to stay close to home for college, playing for Hall of Fame coach Joe Lapchick at St. John's University. Seiden became a star at St. John's, leading the Redmen to two straight National Invitation Tournaments in 1958 and 1959. Seiden averaged 20.4 and 21.9 points per game as a junior and senior and ended his Redmen career with 1,374 points. He served as team captain both seasons[2]
He won a gold medal in basketball with Team USA in the 1957 Maccabiah Games, and was the top scorer in the tournament.[3][4]
In 1959, Seiden led the Redmen to the NIT title as the unseeded 17–9 squad upset the field to win a tournament that was then seen as prestigious as the NCAA tournament. Seiden capped his senior season by being named a consensus second team All-American and won the Haggerty Award as the top player in the New York City metro area.[5]