Born Sept. 23, 1978 in New Orleans, LA, Mackie was raised in the Seventh Ward and for a time, entertained the idea of becoming an engineer like his older brother, Professor Calvin Mackie, who was featured prominently in the Spike Lee documentary "When the Levees Broke" (HBO, 2006). He changed his mind about becoming an engineer after seeing the Challenger shuttle explosion on TV. He believed – as did the rest of the world once the facts were released – that the faulty O-ring engineering caused the shuttle to explode. The disaster effectively ended his engineering fascination. A self-admitted troubled student whose issues were exacerbated by the death of his mother when he was 15, Mackie was encouraged to direct his boundless energy into an after-school theater program; after winning an award from the Speech and Theater League Festival in 1992, Mackie dove headlong into acting. He was soon appearing in local theater productions and on public access television, and by his senior year, he was studying at the North Carolina School of the Arts. A weekend retreat at Julliard convinced him to further his training at the esteemed school; while there, he earned his first critical accolades as rapper Tupac Shakur in the play "Up Against the Wind" (2001), which was brought to Broadway. The success of that show brought more stage work to Mackie, including "Talk," which won him an Obie Award, and understudy to one of his professional influences, Don Cheadle, in "Topdog/Underdog," both in 2002.
That same year, Mackie made his feature film debut as the fearsome Papa Doc, the main antagonist to Eminem's Jimmy Rabbit in "8 Mile." His presence in the film attracted the attention of casting agents, who soon booked him in supporting roles in major studio projects like "Hollywood Homicide" (2003) and "The Manchurian Candidate" (2003). However, it was the independent film "Brother to Brother" (2003) that attracted the most press attention to Mackie's talents. An acclaimed drama about the parallels between the lives of a young art student (Mackie) and a homeless man whose homosexuality made him an outcast during the Harlem Renaissance in the 1920s, the film earned Mackie an Independent Spirit Award nomination in 2004.
Mackie earned his first lead role in a motion picture with Spike Lee's critically lambasted "She Hate Me" (2004), about a disgraced business executive (Mackie) who finds work as a sperm donor to lesbians wishing to have a child. The rancor over the film's subject matter, which helped to sink it at the box office, had little effect on Mackie's career, and he soon graduated to substantial parts in Hollywood features. He provided "Million Dollar Baby" (2005) with one of its most satisfying moments as the loud-mouthed boxer who is silenced by a blow from former fighter-turned-clean-up man Morgan Freeman, and played real-life college football player Nate Ruffin, whose life is forever changed by the death of his teammates in "We Are Marshall" (2006). Mackie also kept a hand in the indie cinema world with notable turns as a dealer in "Half Nelson" (2006) and as anti-slavery fighter Nat Turner in "Ascension Day" (2007).
Mackie received a second Independent Spirit nomination for "The Hurt Locker" (2008), Kathryn Bigelow's Iraq War drama about the physical and emotional strain inflicted on an explosives disposal team. That same year, he reprised his role as Tupac Shakur in the biopic "Notorious" (2009), about the turbulent life of rapper The Notorious B.I.G., and participated in a series of staged readings of August Wilson's plays at the John F. Kennedy Center for the Performing Arts in Washington, D.C.