Pat Finn, one of six children, was born in Evanston, Illinois and grew up in Wilmette, Illinois. He attended high school at Loyola Academy in Wilmette and graduated from Marquette University in Milwaukee, Wisconsin in 1987.

After graduation, he moved to Chicago where he worked as a beer salesman until joining The Second City National Touring Company. During this time, he was also performing improvisation with the ImprovOlympic in Chicago. After writing and performing in two Second City resident shows, Pat landed the part of George Wendt's younger brother in The George Wendt Show.