While attending
Georgetown Law School, Kopf was hired as an offensive assistant by
Lou Little in 1925. Kopf followed Little to
Columbia University in 1930 where he coached the ends and backfield for eight seasons. In 1934, Columbia won the
Ivy League championship, finishing the season with a 7–1 record and a 7–0 win in the
1934 Rose Bowl. Kopf was the head football coach at the Manhattan College from 1938 until the program ended in 1942. His career coaching record at Manhattan was 18–24–1 which ranks him second at Manhattan in total wins and fifth in winning percentage. At the end of the 1942 season, Manhattan College, like many schools of the day, suspended intercollegiate football games because of
World War II. At the end of the war, the college decided not to reactivate the program. Kopf was the school's
athletic director from 1938 to 1944. In 1944, Kopf was named head coach of the
Boston Yanks. This job was supposed to be temporary until
Jim Crowley returned from the Navy. However, instead of coaching the Yanks, Crowley became commissioner of the new
All-America Football Conference and Kopf remained as the Yanks' head coach until 1946. In his three seasons with them, Kopf had a record of 7–22–2. In 1948, he was hired as an assistant under
Denny Myers at
Boston College. He was not retained by new head coach,
Mike Holovak, in 1951. His final coaching job was as an assistant to
Benny Friedman at
Brandeis University. ==Later life and death==