He averaged 6.9 points per game[1] during his two-year National Basketball Association (NBA) career (1949–1951) while also providing half-time entertainment with his accordion performances.

[4] He wrote over a dozen songs while in college, with titles like "I Want a Helicopter" [4] and "You're the Boppiest Bee-Bop",[5] and he also appeared as an accordion soloist for the New Haven Symphony Orchestra.

A 6'3" forward with an accurate one-handed hook shot, he scored 1,964 points in four years and graduated as the fourth highest-scorer in college basketball history.

[5] Eventually, based on suggestions made by sports executive Leo Ferris, Lavelli proposed to join the team on the condition that they would pay him an extra $125 per game to play his accordion during half-time breaks at Boston Garden and certain visitors' arenas.

[1] However, he received much more attention for his half-time accordion performances; indeed, some basketball historians have credited Lavelli's mini-concerts for saving the Celtics franchise, which was in danger of folding due to lack of fans and money.

[10] In a typical performance, Lavelli would greet the fans and play "Granada", "Lady of Spain", and other musical pieces before dashing off to the Celtics' locker room.