On a Morehead-Cain Scholarship, Blackwell earned a Bachelor of Science from the University of North Carolina at Chapel Hill in 1984.

From 2000 to 2006, he was a partner at Blackwell Igbanugo in Edina, Minnesota,[5] one of the nation's largest Black-owned law firms before it was dissolved.

[7][8][9] In 2020, Blackwell obtained a posthumous pardon of Max Mason, a Black man falsely convicted in Duluth, Minnesota, of raping a white woman in 1920.

[10] Blackwell was a special assistant state attorney general for the prosecution during the trial of Derek Chauvin, the Minneapolis police officer who murdered George Floyd.

[11][12] Blackwell served as a pro bono prosecutor and delivered the opening statement and closing argument for the prosecution.