Guy will receive a $2,000 Amway college scholarship for her victory.
She joins Miss Oklahoma 2012 Alicia Clifton in the preliminary talent winners' circle. She won the preliminary on Tuesday night.
A new Miss America will be crowned on Saturday. The final evening of competition and the crowning will be broadcast live on the ABC television network.
Guy is from Swanton. Md. She was graduated from Southern Garrett High School and has attended Cornell University.
Her ambition is to earn a law degree and have a career in law or public service.
Her scholastic achievements include membership on the Cornell Dean's List and Golden Key Honor Society, Alpha Phi Foundation and Mary Miller Lyons Scholarships, Maryland Distinguished Scholar and Carnegie Science Award.
Before being crowned Miss Maryland 2012, she was the reigning Miss Historic.
Her pageant campaign platform is "Heart to Heart: Raising Awareness for Healthy Hearts."