Glenn attended private Catholic school St. Joseph Hill Academy from kindergarten to the 8th grade.

Scarpelli's role as Alex Handris (1980–83) on the long-running television situation comedy One Day at a Time is his most prominent.

Other television appearances include 3-2-1 Contact, Steven Spielberg's Amazing Stories, MacGyver and The Love Boat.

[5] He remained close friends with One Day at a Time co-stars Mackenzie Phillips[6] and Bonnie Franklin until her death in 2013.

[3] In 2021, he began dating television producer John Ricci Jr. whom he met during a benefit for the Hollywood Museum.