Samuelsen taught at Wright State University in Dayton, Ohio before returning to BYU to join the Theatre and Media Arts faculty in 1992. He became head of the Playwriting program in 1999. He has also taught as an adjunct faculty member in the Religion department.
As a playwright, Samuelsen has had many plays professionally produced in throughout the United States. Some of his plays include Gadianton, which has seen three professional productions across the country, A Love Affair with Electrons, Family, The Plan, and The Way We're Wired, which was produced by the Nauvoo Theatrical Society as part of their inaugural season. He is a member of the Playwrights' Circle and the Dramatists Guild. He is three-time winner of the Annual Award in Playwriting offered by the Association for Mormon Letters (AML) and he became president of AML in 2007. In 2013, the organization awarded him the Smith Pettit Award for his lifetime work as a playwright and revered him as a Mormon Henrik Ibsen or Charles Dickens.
His novel, Singled Out, was published by Cornerstone Publishing in 2000. He is also a staff writer for the on-line satirical magazine The Sugarbeet. He was featured in the book Conversations with Mormon Authors, edited by Chris Bigelow and published scholarly articles on 19th and 20th century Scandanavian Theatre, and more recently, on LDS film.
In 2014, the Plan-B Theatre Company, in Salt Lake City, Utah, dedicated their season as a "Season of Eric" in which they showcased four of Samuelsen's plays: Nothing Personal, Radio Hour: Fairyana, Clearing Bombs, and 3.