Jeff Ament has been a member of Pearl Jam since 1990.
Jeff Ament . Along with Stone Gossard , Mike McCready , and Eddie Vedder , he is one of the band 's founding members , and is also known for his work prior to Pearl Jam with the 1980s Seattle-based grunge rock bands Green River and Mother Love Bone , and is particularly notable for his work with the fretless bass , upright bass , and twelve-string bass guitar . Pearl Jam is an American rock band formed in Seattle , Washington , in 1990 .