The band, originally known as The Summerset Big Band, formed in the early 2000's, and was composed of mostly retired seniors. They rehearsed at, and performed mostly for, the various facility events of the Summerset Senior Community; they gradually added events outside of the facilities, including Relay For Life and Race For The Cure. As the years passed, members gradually retired from the group, leading to a more age-diverse set of personnel taking their place; also, the group's balance of exterior-to-interior facility events increasingly favored the exterior.

 Circa 2012, the group then moved out of the facility and renamed itself The Brentwood Big Band (a.k.a. B3), rehearsing in Brentwood and Oakley locations. As the band’s composition continued to adjust, it again renamed itself The East Bay Big Band (a.k.a. EB3) in 2023, to better reflect its area of representation.

 EB3’s current composition is quite age-diverse: it includes high school and college students; active and retired music teachers; as well as regular members of the community. Currently, the band is under the direction of Mr. George Chilcott.