Rothstein began his coaching career in 1966 at
Eastchester High School in
Eastchester, New York and would remain until 1976. During the summer of 1967, he was the athletic director at
Camp Ma-Ho-Ge in
Bethel, New York. He then became assistant coach at
NCAA Division III Upsala College for one season and then worked as head coach at
New Rochelle High School of
New Rochelle, New York from 1976 to 1978. Rothstein returned to Eastchester High for the 1978–79 season and coached varsity basketball and physical education thru June 1983. In 1979, Rothstein signed as a scout for the
Atlanta Hawks and was named assistant coach in July 1983. He was signed as an assistant for the
Detroit Pistons in 1986 before becoming the first coach in Heat history (1988). Rothstein would eventually return to the Heat as an assistant. On January 3, 2007, Rothstein was named as the interim head coach of the Miami Heat in place of
Pat Riley, who took a leave of absence for knee and hip surgery. ==Head coaching record==