She is best known for her roles as attorney Jessica Griffin on the CBS soap opera As the World Turns (1987–1995, 2000–2007, 2009) and as medical examiner Melinda Warner in the NBC police drama Law & Order: Special Victims Unit (2000–2021).

Tunie also appeared in films such as Rising Sun (1993), The Devil's Advocate (1997), The Caveman's Valentine (2001) receiving Independent Spirit Award for Best Supporting Female nomination, Flight (2012), and Whitney Houston: I Wanna Dance with Somebody (2022).

[3] She sang in her church choir, was in the high school band, took dance lessons and was an honor student in the steel-mill town.

[6] She reprised the role from 2000 to 2007, receiving NAACP Image Awards nominations for Outstanding Actress in a Daytime Drama Series in 2003 and 2004.

In the 1990s Tunie guest-starred in primetime dramas including Swift Justice, Law & Order, Chicago Hope, New York Undercover and Sex and the City.

In 2001, she received a nomination for the Independent Spirit Awards for her role in film The Caveman's Valentine, based on George Dawes Green's eponymous novel, opposite Samuel L.

[8] In 2000, Tunie joined the cast of NBC police procedural series Law & Order: Special Victims Unit as medical examiner Melinda Warner.

In 2024, She reprised her role in season four of Law & Order: Organized Crime, reuniting with Christopher Meloni twelve years later.

In 2012, she returned to film, playing Margaret Thomason in the Robert Zemeckis-directed drama Flight starring Denzel Washington.