Harvey Mason Jr. is the son of session drummer Harvey Mason Sr. Damon Thomas was a songwriting and production partner for R&B producer Kenneth "Babyface" Edmonds during the late 1990s, and worked with Babyface on hits such as Dru Hill's "These Are the Times", Faith Evans' "Never Gonna Let You Go", and Pink's "Most Girls".
Harvey Mason Jr. was part of the Darkchild crew working alongside Rodney Jerkins before teaming up with Thomas.
Since then, the duo has worked with a number of R&B performers, among them Lionel Richie, Omarion, J. Valentine, Justin Timberlake, Victoria Beckham, Joe, Donell Jones, Olivia, Mario, JoJo, Mario Vazquez, Stacie Orrico, R. Kelly, Jessica Mauboy, Chris Brown, Jordin Sparks, Marques Houston, Ruben Studdard, Fantasia, Katharine McPhee and more.
Among their work has been the soundtrack for the long-planned film adaptation of the Broadway musical Dreamgirls, featuring performances by Jennifer Hudson, Beyoncé Knowles, Anika Noni Rose, Eddie Murphy, Keith Robinson, and Jamie Foxx.
The Underdogs also produced the Aretha Franklin/Mary J. Blige collaboration "Never Gonna Break My Faith" for the Bobby soundtrack.