Fulton co-founded the Miami Gardens-based Trayvon Martin Foundation following her son's deadly encounter with in 2012.
Fulton says since her son's death, she has advocated to make South Florida communities safer.
Some of the other issues she wants to take on include affordable living and wages.
"Our county must continue moving forward so our families are safe from violence, can afford to live in Miami-Dade, and have access to good paying jobs," she said in her statement, per The Miami Herald. "I am ready to take on these issues and many others in county government."
Fulton will challenge Miami Gardens Mayor Oliver Gilbert for the seat that's up for grabs in 2020 because of term limits, The Associated Press points out.