After graduating from Cedar Cliff High School in Camp Hill, Pennsylvania, he attended Penn State University and received his Bachelor of Fine Arts in Performance.

[4] One of Fabian's earliest prominent roles was as Professor Jeremiah Lasky on NBC's Saved by the Bell: The College Years (1993–1994).

[8] Fabian was cast to play Howard Hamlin, a main role in the AMC television series, Better Call Saul.

[10][11] Fabian's theatre work in New York includes The Food Chain by Nicky Silver,[12] Humpty Dumpty by Eric Bogosian,[13] Six Degrees of Separation (national tour), and, in Los Angeles, Diva by Howard Gould, and Dinner With Friends by Donald Margulies, as well as two seasons at LA's Shakespeare Festival.

Fabian has been a member of SAG-AFTRA's National and Los Angeles Local Board of Directors, running under the Unite for Strength slate.