Roy Simmons Jr. earned honorable mention All-American honors in 1957 and 1958 at Syracuse. An attackman for the Orangemen, Simmons was the second leading scorer at Syracuse in 1957, behind fellow Lacrosse Hall of Fame inductee Jim Brown. In 1958, Simmons was chosen to be team captain, and represented Syracuse in the North/South Collegiate All-Star game.
Following his graduation in 1959, Simmons remained at Syracuse as the freshman lacrosse coach and assistant to his father and fellow Hall of Fame Inductee, Roy Simmons Sr. In 1971, Simmons replaced his father as head coach and remained until retiring after the 1998 season. In 1980, Simmons received the F. Morris Touchstone Trophy as the Division I Coach of the Year. He also coached the North/South Collegiate All-Star game the same year. At the time of his election, his record as head coach at Syracuse was 290-96. He is the only coach to have won six NCAA Division I National Championships (1983, 1988, 1989, 1990, 1993, and 1995). He is one of only two coaches to have won three consecutive NCAA Division I National Championships. His teams made 19 playoff appearances and 16 straight final fours. In 2009, he received the Spirit of Tewaaraton Award.
In 1991, Simmons was also inducted to the Greater Syracuse Sports Hall of Fame and the Upstate New York Chapter of the Lacrosse Foundation Hall of Fame. In addition, he was selected as a Syracuse Letterman of Distinction in 1984.