[2] Classically trained in violin and viola, Freiberg began his career moonlighting as a coffeehouse singer-songwriter (playing acoustic guitar) during the American folk music revival while working for a railroad.

"[3] Following his release, Freiberg co-founded Quicksilver Messenger Service with guitarists John Cipollina, Jim Murray and Gary Duncan and drummer Greg Elmore in 1965.

Due to the surfeit of guitarists in the group, Freiberg (who was only tangentially acquainted with his bandmates through their mutual friendship with Valenti, with Cipollina remarking that they had been instructed to "take care" of him) was assigned the bass.

Freiberg shared lead vocals with Gary Duncan for much of the band's history and regularly contributed additional guitar and keyboards to their studio recordings.

As the "most folk-rooted member" of Quicksilver, he also reworked several songs from the folk revival and singer-songwriter repertoires (most notably Hamilton Camp's "Pride of Man")[2] for the group.

[2] Though not as commercially successful as contemporaries like Jefferson Airplane, Big Brother and the Holding Company and the Grateful Dead, Quicksilver was integral to the development of the San Francisco sound.

[3] Shortly after being released from jail in 1972, Freiberg joined Jefferson Airplane at the behest of Kantner, belatedly replacing Marty Balin on vocals and tambourine for the tour that supported Long John Silver.

[7][8][9] He remained with the group for nearly eleven years, departing shortly after the formation of Starship in early 1985 due to creative differences over the selection and recording of "We Built This City" with Grace Slick (who, according to longtime manager Bill Thompson, considered Freiberg to be "dead weight") and the atypically outsized role of producer Peter Wolf; during this period, Wolf had effectively superseded Freiberg as the band's principal keyboardist in the studio and select live performances.

"[11] Never a prolific songwriter and characterized by Fong-Torres as "essentially a back-up musician"[13] in Jefferson Starship, Freiberg notably served as the primary composer of "Jane.

It has since been prominently showcased in the 2009 video game Grand Theft Auto IV: The Lost and Damned and as the opening theme of the Wet Hot American Summer franchise.

[2] In April 2017, the current members of Jefferson Starship were sued by former lead guitarist Craig Chaquico for not retiring the band's name in the aftermath of Kantner's death.