Boyz II Men's first album, Cooleyhighharmony, was released on Motown in 1991 and was produced by Michael Bivins. Cooleyhighharmony's drum-heavy new jack swing sound and multi-layered sampled backdrops were similar to that of Bell Biv DeVoe's own work, but featured classic-soul styled vocals in place of BBD's rapping and brassier singing. This style was dubbed "hip hop doo-wop" by the group and Bivins, who presented Boyz II Men and adolescent R&B group Another Bad Creation to the public as BBD's protégés.
From the beginning, Boyz II Men featured all four members as leads, avoiding the usual R&B group arrangement of one or two lead singers and a team of background singers. The multiple-lead arrangement became a Boyz II Men trademark, and it became typical to hear Wanya Morris' vibrato-heavy tenor, Shawn Stockman's tenor voice, Nathan Morris' baritone, and Michael McCary's bass (often used in spoken-word sections of many Boyz II Men hits) trading bars in each song.
The album's liner notes identified unique nicknames for each member of the group. These nicknames were devised in collaboration with Bivins in an attempt at marketing. Wanya was "Squirt", Shawn was "Slim", Michael was simply "Bass", and Nathan assumed the name "Alex Vanderpool", after a soap opera character who brandished a nerdy style.
Boyz II Men's first single, the Dallas Austin-produced "Motownphilly" featured a rap cameo by Michael Bivins that gives the story of how he met Boyz II Men. The single's release was accompanied with a music video that presented the group in hip hop style. (The video also included cameos from fellow Philadelphia High School for Creative and Performing Arts alumni Black Thought and Questlove of The Roots.) Cooleyhighharmony's second single was an a cappella cover of a classic Motown tune, G.C. Cameron's "It's So Hard to Say Goodbye to Yesterday" from the 1975 film Cooley High, while "Uhh Ahh" served as the third single.
Cooleyhighharmony achieved major success, eventually selling over nine million copies and winning the Grammy Award for Best R&B Performance by a Duo or Group with Vocals at the 1992 Grammy Awards. Boyz II Men were also nominated for Best New Artist, along with British singer-songwriter Seal, fellow R&B group Color Me Badd, as well as dance group C+C Music Factory, but the Grammy was awarded to singer-songwriter Marc Cohn. "Motownphilly" and "It's So Hard to Say Goodbye to Yesterday" were number 1 R&B hits and top five U.S. pop hits.