Keymáh was born Crystal Walker in 1962, in Chicago. Since the age of three, she has enjoyed entertaining her family – singing, dancing, and reciting original poems and stories. She wrote her first play and her first song in elementary school. She performed with Ali LeRoi and Lance Crouther in the Mary Wong Comedy Group in high school, before she enrolled in Florida A&M University (FAMU) at the School of Business and Industry. Her brother is Commander of the DC US Army National Guard, Major General william J. Walker.

Some of My Best Friends is a series of monologues in verse and prose embodied by a dozen diverse but somehow connected characters. In this humorous, tear jerking, thought-provoking theatrical production, Keymáh champions societal issues that are as relevant today as they were when the show debuted to sold out crowds at Chicago's South Shore Cultural Center in 1991. Overcoming obstacles, the devastation of AIDS, the search for love, race relations, and teen promiscuity are just some of the topics explored. The show was chiefly penned by Keymáh but includes pieces written by or in collaboration with Ali LeRoi, Harry Lennix, and poet Angela Jackson (And All These Roads Be Luminous: Poems Selected and New); and includes a dance choreographed by Maurice Hines. About her work in this show critics have said: "Keymáh is a Charismatic Actress... Chameleonic and Effervescent" – Los Angeles Times;"...Beyond Superlatives; She's Phenomenal!" – Earl Calloway, Chicago Defender; "Much More Than Comedy"- Lisa M. Pancia, New York Vignette; "...a Delightful, Multitalented Performer whose ability to create believable characters on stage is a Wonder to Behold"- Nat Colley, Los Angeles Reader; “Keymáh is Magnificent” – Linda Armstrong, Amsterdam News;"...Keymáh’s Poignant, Detailed Portrayals are Never Less Than Magnificent"- Randy Trabitz, Los Angeles Weekly. The show garnered an AUDELCO Award nomination for Best Solo Performer, an NAACP Theatre Award nomination for Best Writing, and NAACP Theatre Awards for Best Performance and Best Play.

T'Keyah Live! is a variety show and is Keymáh's third self-produced theatrical show. It includes witty repartee, musical numbers, endearing characters, audience participation, impressions, video presentations, jokes and guests. She has performed the show across the U.S. since 1999 with a number of different guest performers, including Todd Bridges, T. C. Carson, Ralph Harris, Dawnn Lewis, and Karen Malina White.

Keymáh performed a solo stage work titled Don't Get Me Started! She sang, performed impressions, and talked about the prison industrial complex as well as conspiracy theories. She rewrote pointedly political lyrics to songs by Nina Simone and Eartha Kitt. She debuted the show in 2011 at The Black Academy of Art & Letters (TBAAL) in Dallas, Texas.

T'Keyah Crystal Keymáh served as a K–8 substitute Teacher for the Chicago Board of Education for 4 years. She has presented her "Tools of the Trade" actors preparation workshops at theatre festivals and other events in the United States, and she has lectured abroad. In the fall of 2017, Keymáh served as Florida A&M University's first ever W.K. Kellogg Foundation Artist-in-Residence in the College of Social Sciences, Arts, and Humanities Theatre department. Her residency included directing Pearl Cleage's The Nacirema Society Requests Your Presence at a Celebration of Their First 100 Years, teaching an Acting for the Camera course, and providing industry workshops and mentoring students.