He is best known for his work in the 1960s with Tim Hardin, the Lovin' Spoonful, the Charlatans, and Sopwith Camel, and later with Norman Greenbaum, Tazmanian Devils and Chris Isaak.

[1] His early musical influences were wide-ranging, including a unique opportunity to listen to the first urban radio stations broadcasting polka, blues and country.

[3] In 1964, after hearing the Beatles, Jacobsen quit the Knob Lick Upper 10,000, intending to produce records that combined folk music with electric instruments and drums.

Returning to New York, he soon met John Sebastian, who had similar ideas, and they began working with other musicians, including Jerry Yester, Zal Yanovsky, Jesse Colin Young, Cass Elliot, and Denny Doherty.

[5] The Lovin’ Spoonful also recorded soundtracks for Woody Allen's first movie What’s Up Tiger Lily as well as Francis Ford Coppola's You're a Big Boy Now.

Jacobsen expanded his search for talent to California and worked there with the first of the newly emerging San Francisco rock bands, The Charlatans.

While having little recording success, the band served as a launching pad for the songwriter and singer Dan Hicks, composer of the iconic song "I Scare Myself," among many others.

[2] They made three albums together, and Jacobsen produced Greenbaum's "Spirit in the Sky",[2] which became a number one worldwide hit and went on to be one of the most licensed recordings of all time, appearing in many TV shows, films, and commercials.

In 1980–1984, he produced two albums with the San Francisco ska- and reggae-oriented band Tazmanian Devils on Warner Brothers Records.