Goodman had one daughter, Mercy Tannen, whom Marty McFly became interested in upon seeing her. However once knowing who her father was, he backed down. Due to Marty's strange antics and sayings, Mercy, Goodman, and the townsfolk looked at "the stranger" with disdain. After Marty played his harmonica, Goodman and the townsfolk deemed him a witch and prepared to forgo the water test.
After Marty presumably drowned in the water test, they believed that he was innocent and ceased their ways, with Goodman assumed to follow along.