Mr. Harter is the main antagonist of The Three Stooges. He is Teddy's adopted father.
Mr. Harter was a rich man who married women to get rich and not out of love. He came to an orphanage to adopt an orphan. He initially chose Moe but as they drove off in their car Moe asked if he could go back and adopt his two friends, Larry and Curly. Mr. Harter thought three kids were too much and dropped Moe off back at the orphanage and adopted a young Teddy.
When Mrs. Harter died, she gave her fortune to Teddy. Mr. Harter was displeased and teamed up with Lydia, Teddy's wife, to kill him and take the money for themselves. Lydia tried to get the now adult Three Stooges to kill Teddy but they hospitalized Mac, thinking he was the husband.
Later on, Larry and Curly met up with Mr. Harter and asked if he could give them the money they needed to save the orphanage. However, Mr. Harter was too greedy and told them to call him only if they needed to sue someone. He also revealed he dropped Moe off because he requested bringing them, which they did not know because Moe told them they dropped him off because he didn't do chores.
Later on in the Lydia and Mac capture Teddy and the Three Stooges. However, Mr. Harter appears with a gun and appears to be about to save them when it is revealed he was working with Lydia and that Lydia was using Mac to do their dirty work. They hold the five of them hostage and drive off in a car when the Three Stooges pet rat comes out and lands on Lydia's chest, causing them to freak out and drive their car into a lake. The police arrive and Harter, Lydia, and Mac are arrested.