Green is fourth former Philly mayor to make an endorsement in the Philadelphia mayor race and the first who is not lining up behind former City Controller Rebecca Rhynhart.
The last debate in the Philadelphia mayor's race featured a heated back-and-forth over ethics, odd attacks over union endorsements, and new scrutiny for one candidate.
Candidates for Philadelphia mayor will debate at the 6abc studio on April 25. Amen Brown, Jeff Brown, Allan Domb, Helen Gym, Cherelle Parker, and Rebecca Rhynhart will participate.