The Reds won the first game of an important series against the Pittsburgh Pirates on Friday evening, 3-0.
What's more, the first game of the series was called a 'Marty Party'.
The longtime broadcaster for the Reds said he would shave his head if Cincinnati won 10 games in a row - Which they did.
He then said he would go bald at the ball park if fans donated at least $20,000 to the Reds Community Fund - Which they did.
Therefore, after Friday's game, fans stuck around to see Brennaman shave his lustrous, poofy hair, right on the field.
Other post game activities included a celebration for Brennaman's 70th birthday, on July 28th. He was presented with a cake and a 'Happy Birthday' song from the crowd.
In addition, there was a postgame fireworks show to a soundtrack picked by Marty, himself.
You go, Marty Brennaman!