Day started singing in church in Brooklyn. She attended the prestigious High School of Music and the Performing Arts, and went on to study musical theater at the University of Bridgeport in Bridgeport, Connecticut.
Day has also appeared on Broadway, notably as understudy to Stephanie Mills as “Dorothy” in The Wiz, and stepped into the lead role in Washington, D.C. and St. Louis, Missouri.
She has had extensive experience as a session musician, having appeared on tracks by Michael Jackson, Al Green, Sean “Puffy” Combs, MC Lyte, Queen Latifah, Monie Love, Big Daddy Kane and Jonathan Butler. Day has also written songs for Randy Crawford and Bootsy Collins, and has writing credits on Missy Elliott’s”Gossip Folks” (the second single from her Under Construction album), on which Day co-wrote the hook and provided backing vocals.
Day was introduced to house music in 1996 when she was asked to do a demo. She met German record producers Boris Dlugosch and Mousse T, who produced a dance single “Keep Pushin”, which went on to reach #2 on the Billboard dance charts. She then sang chorus for Mousse T’s track “Horny”, which later gained in popularity when additional vocals from the duo Hot ‘N’ Juicy were added to the song. “Horny” reached #1 on the Billboard dance chart. The follow-up song “Hold Your Head Up High”, with Booom!, reached #6 on the Billboard dance chart.
In 2004 she sang on a track by the Australian dance producer mrTimothy called “I Am Tha 1”, credited to Mr Timothy featuring Inaya Day, which went to the top of the Australian dance charts and top 30 in the Australian pop charts. She also sang on his next single “Stand By Me” later that year. “Nasty Girl” was first released in Australia, reaching the top 20, and it was then released in the UK in July 2005, and reached #9 there. Later that year, she also guest featured on “The Glamorous Life”, a single by T-Funk, an alternate alias of mrTimothy. In June 2007, Day released a cover version of the 1988 Big Pig song, “Breakaway”.