White previously ran for mayor, in both 2011 and 2013, on the Green Party line.
But this year, he said he will also run as a Democrat.
“In this new political climate of uncertainty, Rochester needs to stop looking to others to save us, and start marshaling our resources to create the institutions which will build a stronger Rochester,” White said in a press release.
Monroe County Legislator James Sheppard, and former WROC-TV news anchor Rachel Barnhart have also announced they are seeking the Democratic nomination.
Incumbent Mayor Lovely Warren has not yet said whether she will run for re-election.