Margolin will receive a cash prize of $15,000. Tanya Barfield earned an honorable mention for her play Blue Door. She receives $5,000.
The awards will be presented at The National Arts Club on Nov. 20.
Theatres from across the country were invited to nominate playwrights "who show exceptional promise, but have not yet received prominent national attention." Thirteen theatres participated in this year's process, and winners were chosen by three judges: playwright John Guare; playwright and performer Eric Bogosian and Lincoln Center dramaturg Anne Cattaneo. Margolin was nominated by the Cleveland Public Theatre. Seattle Rep nominated Barfield.
The Kesselring Prize is named in honor of Joseph Kesselring, who penned Arsenic and Old Lace. Previous winners of the award include David Auburn, Tony Kushner, Nicky Silver, Anna Deavere Smith and David Lindsay Abaire.