Everything Will Be Different, about a tortured teenager struggling to deal with her indifferent father, a sense of worthlessness, and flood of accompanying emotions, had its New York debut at Soho Rep in 2005.
The play was submitted to the Kesselring committee by MCC theatre under the title A Brief History of Helen of Troy.
Schultz will receive a cash prize of $15,000.
Bruce Norris earned an honorable mention for his play The Pain and the Itch. He receives $5,000.
The awards will be presented at The National Arts Club on Nov. 19. 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.
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.