Pearl Jam is an American rock band formed in Seattle, Washington, in 1990. Since its inception, the band's line-up has consisted of Eddie Vedder (lead vocals), Mike McCready (lead guitar), Stone Gossard (rhythm guitar) and Jeff Ament (bass). The band's fifth member is drummer Matt Cameron (also of Soundgarden), who has been with the band since 1998. Boom Gaspar (piano) has also been a session/touring member with the band since 2002.

Stone Gossard and Jeff Ament were members of pioneering grunge band Green River during the mid-1980s. Green River toured and recorded to moderate success but disbanded in 1987 due to a stylistic division between the pair and bandmates Mark Arm and Steve Turner. In late 1987, Gossard and Ament began playing with Malfunkshun vocalist Andrew Wood, eventually organizing the band Mother Love Bone. In 1988 and 1989, the band recorded and toured to increasing interest and found the support of the PolyGram record label, which signed the band in early 1989. Mother Love Bone's debut album, Apple, was released in July 1990, four months after Wood died of a heroin overdose.  Ament and Gossard were devastated by the death of Wood and the resulting demise of Mother Love Bone. Gossard spent his time afterwards writing material that was harder-edged than what he had been doing previously. After a few months, Gossard started practicing with fellow Seattle guitarist Mike McCready, whose band, Shadow, had broken up; McCready in turn encouraged Gossard to reconnect with Ament. After practicing for a while, the trio sent out a five-song demo tape in order to find a singer and a drummer. They gave former Red Hot Chili Peppers drummer Jack Irons the demo to see if he would be interested in joining the band and to distribute the demo to anyone he felt might fit the lead vocal position.  Irons passed on the invitation but gave the demo to his basketball friend, San Diego, California singer Eddie Vedder. Vedder was the lead vocalist for a San Diego band, Bad Radio, and worked part-time at a gas station. He listened to the tape shortly before going surfing, where lyrics came to him. He then recorded the vocals to three of the songs ("Alive", "Once", and "Footsteps") in what he later described as a "mini-opera" entitled Momma-Son. Vedder sent the tape with his vocals back to the three Seattle musicians, who were impressed enough to fly Vedder up to Seattle for an audition. Within a week, Vedder had joined the band.  With the addition of Dave Krusen on drums, the band took the name Mookie Blaylock, in reference to the then-active basketball player Mookie Blaylock. The band played its first official show at the Off Ramp Cafe in Seattle on October 22, 1990. They opened for Alice in Chains at the Moore Theatre in Seattle on December 22, 1990, and served as the opening act for the band's Facelift tour in 1991. Mookie Blaylock soon signed to Epic Records and renamed themselves Pearl Jam. In an early promotional interview, Vedder said that the name "Pearl Jam" was a reference to his great-grandmother Pearl, who was married to a Native American and had a special recipe for peyote-laced jam. In a 2006 Rolling Stone cover story however, Vedder admitted that this story was "total bullshit", even though he indeed had a great-grandma named Pearl. Ament and McCready explained that Ament came up with "pearl", and that the band later settled on "Pearl Jam" after attending a concert by Neil Young, in which he extended his songs as improvisations of 15-20 minutes in length.

When did they form their band?
In 1988 and 1989, the band recorded and toured to increasing interest and found the support of the PolyGram record label, which signed the band in early 1989.