Irwin was born and reared in New York City and, while he never hiked miles to school, he did walk up six flights of stairs every day to the apartment his family lived in until he was nearly 19. Irwin remains a lover of subway rides, egg creams, and the New York Mets. He moved to Maine in 1978 and worked a dozen years in commercial radio in Sanford, then Portland, before beginning to freelance for MPBN in 1990. He's been local anchor of Morning Edition since September, 1992.

From September 2004 to October 2005, Irwin served as national President of the Society of Professional Journalists, the nation's largest and most broad-based journalism organization. He holds a Master's Degree in Journalism from New York University.

Irwin also has an interest in astronomy which he indulges to this day as an occasional show presenter at the Southworth Planetarium in Portland. And he swims - a lot. Irwin has completed 5 Peaks Island-to-Portland swims. Irwin is married and has a young son.