The Beavers finished 10–4 in his first year on varsity, including a close four-point loss to the defending national champions, New York University.

The following year, he accounted for approximately one-fifth of CCNY's total scoring (119 out of 596 points) en route to a 10–6 record.

That season, Basketball Hall of Fame coach Clair Bee said that Fliegel was "...the best player in the city.

In a game against All-American Hank Luisetti and the Stanford Cardinal (who had three players taller than Fliegel) at Madison Square Garden, he almost led a stunning comeback after being down by 16 points in the second half before falling, 45–42.

He also began playing professionally in the American Basketball League (ABL) for Kate Smith's Celtics, but the team moved shortly thereafter and became known as the Kingston Colonials.

For the rest of his professional career, which was interrupted for three years due to his enlistment in the U.S. Army for World War II, he played for either the Wilmington Bombers or Jersey City Atoms.

Fliegel was offered to play for the New York Knicks in the newly developed Basketball Association of America (which became the modern NBA), but his desire to practice law made him refuse the invitation.