Mckesson, who became a key member of the Black Lives Matter movement during the protests in Ferguson, Mo. last summer, is the 13th and final candidate, according to the Baltimore Sun. Current mayor Stephanie Rawlings-Blake will not be seeking reelection, saying that she wants to focus her energies on healing the city in the wake of unrest over the death of Freddie Gray, who suffered fatal injuries while in police custody almost a year ago.

Mckesson, a Baltimore native, wrote in a Medium post Wednesday that his status as an outsider is a strength for his candidacy. “I have come to realize that the traditional pathway to politics, and the traditional politicians who follow these well-worn paths, will not lead us to the transformational change our city needs,” he writes. “I am running to be the 50th Mayor of Baltimore in order to usher our city into an era where the government is accountable to its people and is aggressively innovative in how it identifies and solves its problems.”

Mckesson was on Fortune’s 50 Greatest Leaders list last year for his involvement in the Black Lives Matter protests. The activist participated in protests following the death of Freddie Gray. As a member of Campaign Zero, a movement to end police brutality, Mckesson has met with White House officials and politicians to discuss civil rights.