The band was originally composed of Eric Martin (lead vocals), Paul Gilbert (guitar), Billy Sheehan (bass), and Pat Torpey (drums).

Following Torpey's death in 2018, the band went on hiatus, and later conducted a farewell tour in 2023 with former Spock's Beard dummer/vocalist Nick D'Virgilio.

Sheehan had originally intended to complete the band with guitarist Steve Stevens and drummer Gregg Bissonette (who Sheehan had played with in Roth's backing band),[11] but this fell apart when Stevens opted to pursue his Atomic Playboys project and Bissonette decided to stay with Roth.

Torpey, a journeyman session drummer, had previously recorded and toured with a number of high-profile artists, including Impellitteri, Stan Bush, Marilyn Martin, Belinda Carlisle, Ted Nugent, The Knack, and Jeff Paris (who would later collaborate with Mr. Big in a songwriting capacity).

Several band names were considered, including "Wild Blue Yonder", "Red House", "Hawks and Doves", "Mars Needs Women" and "Magic to Burn", before Torpey suggested "Mr. Big", a nod to the song by Free.

[12][13] By 1989, they signed with Atlantic Records and released their self-titled debut the same year, which charted just outside of the top 40 stateside[14] and was also successful in Japan.

In August 1990, two songs, "Strike Like Lightning" and "Shadows", performed by Mr. Big, were exclusively released on the soundtrack album of the action film Navy SEALs.

[16] Mr. Big's second album, 1991's Lean Into It, was a major commercial breakthrough, especially two ballads, "To Be with You" (which went to number one in fifteen countries) and "Just Take My Heart", as well as the song "Green-Tinted Sixties Mind".

Gilbert left the band in 1999, and eventually reformed Racer X. Richie Kotzen, another Shrapnel artist and former guitarist for Poison, was brought in as a guitar player.

Although Sheehan was upset that the other members had attempted to "fire" him from the band he created, he agreed to rejoin them, provided that that would be their farewell tour.

[19] A near Mr. Big "one-off" reunion took place on May 13, 2008, in Los Angeles, at the House of Blues, when Paul Gilbert was joined on stage by Pat Torpey, Richie Kotzen, and Billy Sheehan, for renditions of Humble Pie's "30 Days in the Hole" and original Mr. Big composition "Daddy, Brother, Lover, Little Boy".

A press conference in Japan in February generated much excitement,[21] and a tour of the country starting in June was announced, with shows in ten locations (including the Budokan).

They held their first reunion concert outside Japan at Rock Cafe in Tallinn, Estonia, in September 2009, continuing their tour.

In September 2010, Mr. Big recorded a seventh album with producer Kevin Shirley at a Los Angeles-area studio.

[25] The tour to support the album kicked off at The House of Blues, in Hollywood, California, on April 2, 2011, and ended at the Rockout Festival in Istanbul, Turkey, in October 2011.

The band confirmed that Pat's fill-in for the upcoming world tour would be Burning Rain drummer Matt Starr, who had also previously performed with Ace Frehley and Joe Lynn Turner.

The group's latest album, Defying Gravity, was recorded in Los Angeles in six days, and released on July 21, 2017.

A memorial show took place on May 23, 2018, at The Canyon in Agoura Hills, California, with former member Richie Kotzen as a special guest.

[31] The all-star finale of "To Be With You" included, among others, Matt Sorum, Dave Amato, Ricky Phillips, Keith St John, Prescott Niles, Kelly Keagy, Jeff Scott Soto, Ace Von Johnson and Gregg Bissonette.

In October 2018, Eric Martin said in interview with Friday NI Rocks that the band was in the process of planning their at-that-time possible next and final album.

[34] However, in a later interview he announced that the band have decided not to continue with Starr as their drummer due to his "vocal range" being different to Torpey's.

[37] Despite having announced a farewell tour, Martin confirmed in November 2023 that the band were still working on new material for their tenth studio album.