Kotis studied political science at the University of Chicago. He dropped out when he took a course on the Short Comic Scene, realizing that he wanted to be part of the theatre industry instead. Kotis started working with (and became a member of) the Cardiff Giant Theatre Company and the Neo-Futurists. In 1995 he and his wife, writer and actor Ayun Halliday, moved to New York. They worked day jobs, and then quit them when theatre work came along. They remained in fringe theatre until he started work on Urinetown.
He is best known for writing the book and co-writing the lyrics of Urinetown the Musical. He got the idea for Urinetown the Musical when, on an ill-budgeted visit to Paris in 1995, he had to limit his trips to the pay toilets that are ubiquitous in that city.Urinetown the Musical received ten Tony Award nominations: Best Director, Best Original Score, Best Book of a Musical, Best Musical, Best Actor in a Musical, two nominations for Best Actress in a Musical (Nancy Opel and Jennifer Laura Thompson), Best Featured Actress in a Musical, Best Choreography, and Best Orchestration. Urinetown has been performed around the world and in hundreds of American cities.
His most recently produced play is Pig Farm, which premiered at The Roundabout Theatre in New York City in June 2006.
He has appeared on stage with and written for the Neo-Futurists and Cardiff-Giant. He holds a degree in political science from the University of Chicago where he was a member of Off-Off Campus. He and Halliday have two children, India and Milo.