Harrison Miles handed Reiss’s side ahead on 32 minutes, before Divine Mukasa drilled home his 12th goal of the season.
Kaden Braithwaite was sent off and conceded a penalty before the hour mark and Oliver Pickles dispatched the spot kick.
Leeds completed the comeback when Joe Billett’s high, looping effort from far out beat Max Hudson draw the game level.
Reiss was happy to see his City players fight to stay in the game, but late on, Divine Mukasa struck a winner and give his team an eleventh consecutive league win.
MATCH REPORT | CITY 3-2 LEEDS - UNDER-18S PREMIER LEAGUE NORTH
“We have never been in this situation before with one man down and not so often in the past have we been in a situation where the end of the game was so tight,” Reiss expressed.
“So we were struggling a little bit because this was a new situation for us and I’m very happy for this.
“We could see that we needed a little bit support in a tactical way with how to defend and how to attack with one man down, because of course this is a new situation, but the they did well well.
“It is not a tactical thing or we don’t know how we play with the ball in a beautiful way, we had to fight for this win and it is very good for me to see that all of the players were able to do this.”
Listen to all of Reiss’ post-match thoughts via his interview in the video above …