Having worked as a DJ at WXPN in Philadelphia, Unterberger started reviewing records for Op magazine in 1983. From 1985 to 1991, he was an editor for Option.
Since 1993, he has been a prolific contributor to allmusic, the on-line database of music biographies and album reviews, for which he has written thousands of entries. (Many of his on-line contributions have been printed in the AllMusic guide series.) Unterberger contributes to various local and national publications, including Mojo, Record Collector, Rolling Stone, Oxford American, and No Depression. He has written liner notes for dozens of CD reissues from labels like Rhino, Collectors' Choice, and Sundazed.
Unterberger's books draw extensively on first-hand interviews  with musicians and their associates.
Unterberger has given numerous talks on music and popular culture at public libraries in San Francisco, Berkeley, and San Mateo County, California. He is also a speaker at area bookstores, including The Booksmith in the Haight Ashbury neighborhood of San Francisco.
Unterberger has also written on travel, including The Rough Guide to Seattle (1996), and is co-author of The Rough Guide to Shopping with a Conscience (2007), a book about ethical products, investment, and related topics. He has traveled to more than thirty countries and is an advocate of independent travel and alternative culture.
His nephew, Andrew, formerly wrote for Stylusmagazine.com, and in 2007 was part of the winning team on VH1's World Series of Pop Culture. He has been a staff writer or featured contributor on a number of music or sports blogs.
1998: Unknown Legends of Rock'n'Roll. Profiles of 60 underappreciated cult rock artists of all styles and eras
1999: The Rough Guide to Music USA. A guidebook to the evolution of regional popular music throughout America in the twentieth century
2000: Urban Spacemen & Wayfaring Strangers: Overlooked Innovators and Eccentric Visionaries of '60s Rock. Another look at underappreciated cult rock artists
2002: Turn! Turn! Turn!: The '60s Folk-Rock Revolution. The first part of a history of folk rock
2003: Eight Miles High: Folk-Rock's Flight from Haight-Ashbury to Woodstock. The second part of a history of folk rock
2006: The Unreleased Beatles: Music and Film. An illustrated 400-page guide to music that the Beatles recorded but did not release, as well as musical footage of the group that has not been made commercially available (winner of a 2007 Award for Excellence in Historical Recorded Sound Research from the Association for Recorded Sound Collections)