She grew up in New Jersey until about age three; her family moved to Syosset, New York on Long Island. Her parents are Stuart Mentzel, a pajama salesman, and Helene Goldberg, a therapist. She has a younger sister named Cara. Idina Menzel is Jewish and her grandparents emigrated from Russia.

At 15, she started to work as a wedding & bar mitzvah singer. She attended Syosset High School & graduated from New York University's Tisch School of the Arts w/ a degree in drama in 1992. In 1996, she debuted in theater, originating the role of Maureen in Rent, which went from Off-Broadway to Broadway.

Idina Menzel provided both the singing and speaking voice of Elsa. Eva Bella and Spencer Ganus were cast to portray Elsa as a young child and as a teenager, respectively. Actress and singer Megan Mullally was originally cast to voice an adult Elsa, but was replaced by Idina Menzel.

The Tony winner has one son, 13-year-old Walker, with ex-husband Taye Diggs. Three years after her and Diggs' 2014 divorce, she married actor Aaron Lohr, and having kids wasn't initially in the new couple's plans.