Reinking was born in Seattle, Washington, Frances (née Harrison) and Walter Reinking. She grew up in the suburb of Bellevue. As a child, Reinking began ballet lessons, studying with former Ballets Russes dancers Marian and Illaria Ladre in Seattle.
Reinking made her professional performing debut at the age of 12 in a production of Giselle with the English Royal Ballet.
Reinking moved to New York City at age 18, and danced as a member of the corps de ballet at the Radio City Music Hall, performed in the ensemble of the second national tour of Fiddler on the Roof, and at the age of 19 made her Broadway debut in the musical Cabaret. She was a chorus dancer in Coco (1969), Wild and Wonderful (1971), and Pippin (1972). During Pippin she came to the attention of the show's director and choreographer Bob Fosse. Reinking became Fosse's protégé and romantic partner.
In 1974, Reinking came to critical notice in the role of Maggie in Over Here!, winning a Theatre World Award. She starred as Joan of Arc in Goodtime Charley in 1975, receiving Tony Award and Drama Desk nominations for Best Actress in a Musical.
In 1976 she replaced Donna McKechnie as Cassie in A Chorus Line; in 1977 she replaced Gwen Verdon in the starring role of Roxie Hart in Chicago, a show directed and choreographed by Fosse. In 1978 she appeared in Fosse's review Dancin', and received another Tony nomination.
In that year Reinking and Fosse ended their romance and separated. They continued to have a professional, creative collaboration. Reinking has acknowledged Fosse as the major influence on her work as a choreographer.
In 1979, Reinking appeared in Bob Fosse's semi-autobiographical film All That Jazz as Katie Jagger, a role loosely based on her own life and relationship with Fosse.
Reinking remained in Hollywood for several years after All That Jazz, and appeared in two more feature films, Annie (as Grace Farrell) and Micki & Maude (as Micki).
In March 1985, Reinking appeared at the 57th Academy Awards to give a mostly lip-synced vocal performance accompanied by a dance routine of the Academy Award-nominated Phil Collins single "Against All Odds (Take a Look at Me Now)". The routine was poorly received by critics from the Los Angeles Times and People, as well as by Collins himself in a Rolling Stone interview.
In 1986, she returned to Broadway, starring in a successful revival of Fosse's production of Sweet Charity. In 1991, she appeared in her first theater production following the birth of her son, the Broadway National Tour of Bye Bye Birdie, costarring Tommy Tune. In 1992 she contributed choreography to Tommy Tune Tonite!, a three-man review featuring Tune.
Reinking founded the Broadway Theater Project, a Florida training program connecting students with seasoned theater professionals, in 1994. In 1995, she choreographed the ABC television movie version of the Broadway musical Bye Bye Birdie.
Reinking had retired from performing by this time. In 1996, she was asked to create the choreography "in the style of Bob Fosse" for an all-star four-night-only concert staging of Chicago for City Center's annual Encores! Concert Series. When the producers could not obtain a suitable actress for the role of Roxie Hart, Reinking agreed to reprise the role after almost 20 years. This concert staging of Chicago was a hit, and a few months later the production (in its concert staging presentation) was produced on Broadway, with the Encores! cast: Reinking, Bebe Neuwirth, Joel Grey, James Naughton, and Marcia Lewis. In November 2016 the revival celebrated its 20th year, and as of at least September 2017 it is the longest-running American musical on Broadway. The revival of Chicago won numerous Tony Awards, and Reinking won the Tony Award for Best Choreography. She recreated her choreography for the 1997 London transfer of Chicago, which starred Ute Lemper and Ruthie Henshall.
In 1998 she co-created, co-directed and co-choreographed the revue Fosse, receiving a Tony Award co-nomination for Best Direction of a Musical. For her work on the West End production of Fosse, Reinking (along with the late Bob Fosse himself) won the 2001 Olivier Award for Best Theatre Choreographer.
In 2001, she received an honorary doctorate from Florida State University for her contribution to the arts.
Reinking served as a judge of annual New York City public school dance competitions for inner-city youth, and appeared in Mad Hot Ballroom, the 2005 documentary film about the competition. In 2012, she contributed choreography for the Broadway production of An Evening with Patti LuPone and Mandy Patinkin. She has served as a member of the advising committee for the American Theatre Wing.
Reinking has been married four times, first in 1970 to Larry Small. Following their divorce, she married investment banker Herbert Allen, Jr. on August 25, 1982; they divorced in 1989. Next she was married in 1989 to businessman James Stuart, with whom she had one child, son Christopher, before their divorce in 1991. Reinking has been married since 1994 to sportswriter Peter Talbert, and is stepmother to Leslie, Christie, Herbert, and Charlie.
As of at least 2009, Reinking lives primarily in Phoenix, Arizona.
Reinking's son, Chris, suffers from Marfan syndrome, and Reinking works with the Marfan Foundation, which is dedicated to raising awareness of the disease. She produced the 2009 documentary In My Hands: A Story of Marfan Syndrome."Ann Reinking & Gary Chryst: Big Noise from Winnetka". Jacob's Pillow Dance Festival. June 21, 1987. Retrieved September 10, 2017.