He became friendly with other young musicians and songwriters in the area, including Peter Sabatino, Leslie West, Tom Feher, and Michael Brown, and wrote several songs for West (then known as Weinstein)'s band, the Vagrants, including their single "Beside the Sea", co-written with producer Felix Pappalardi and his wife Gail Collins.

The group (which included Michael McKean on bass) soon fell apart, following legal threats by original Left Banke singer Steve Martin's lawyers.

In the same baroque vein as the Left Banke, Sommer wrote "Brink of Death", recorded by the band Childe Harold with an arrangement by Wendy Carlos.

[9] Sommer continued to perform in and around New York, often opening the bill for major acts such as Ike and Tina Turner and the Byrds.

After being encouraged to audition by music producer Artie Ripp, he appeared as "Flatbush" of Kaptain Kool and the Kongs on The Krofft Supershow in 1976, but he did not reprise the role in the second season.

In 1977, his fourth album, also titled Bert Sommer, produced in Los Angeles by Ron Dante, was released by Capitol Records.

[10] The follow-up album that never happened, to have been produced by Trevor Lawrence, contained songs such as "You", featured in the films The Patriot (1986) and Stella (1990).

[10] Sommer returned to Albany in August 1983 and almost immediately began to perform in local venues with Johnny Rabb, as well as Carla and Kevin McKrell, in The Fabulous Newports.