Winners will each receive a $50,000 award during a ceremony at the New York Public Library on Sept. 23.
"It is an incredible honor," Lehmann, 43, said Thursday between interviews of prospective science teachers.
"Obviously, this award is shared with the entire SLA community. This does not happen without the teachers, students, parents, and the support from the Franklin Institute. It does not happen without the School District creating the conditions so we can innovate."
Now in its 27th year, the prize is awarded to innovators in education. Past winners have included Wendy Kopp, founder of Teach for America, and Barbara Bush, founder of the Barbara Bush Foundation for Family Literacy.
In the announcement, the foundation called Lehmann a "national ed-tech thought leader," and said SLA "tackles the achievement gap in science, technology, engineering, and mathematics (STEM) subjects for highly qualified minority students."
The foundation said that the college-prep school's inquiry-driven curriculum was enhanced by a program that gives every student a laptop.
Lehmann, who is not sure how he was nominated, said he had not had a chance to think about how he would spend the cash award.
A onetime teacher in New York City, Lehmann came to Philadelphia in 2005 to create SLA, one of the small, specialty high schools launched when Paul Vallas was the district's CEO.
Established in partnership with the Franklin Institute, SLA opened the following year as a project-based school with focuses on science, technology, math, and entrepreneurship. The school has attracted national attention for its practices, including being featured in a PBS documentary and named an Apple Distinguished School.
The success of the 500-student academy prompted the School Reform Commission and Superintendent William R. Hite Jr. to open a second SLA campus at Beeber Middle School in Overbrook Park last September. The nonprofit Philadelphia School Partnership gave a grant to help.
As the cash-strapped district awaits word on whether the state House will return to Harrisburg to vote on a bill that would allow the city to impose a $2-per-pack tax on cigarettes to raise money for schools, Lehmann said he hoped that the national recognition the award will bring could help.
"I'm hopeful that the state will do the right thing and understand that Philadelphia public schools have to be funded," he said. "If the SLA recognition in any way is something that Dr. Hite and the SRC can use as a proof point for what can happen in Philadelphia, we are thrilled to stand with our colleagues in the district to continue to lobby for the necessary support for our schools."
The other winners in the 2014 Harold W. McGraw Jr. Prize in Education are: Andreas Schleicher, director for education and skills and special adviser on education policy to the secretary-general at the Organization for Economic Cooperation and Development in Paris, who won the Global Leadership Prize, and Sara Martinez Tucker, CEO of the National Math and Science Initiative in Dallas, winner of the National Leadership Prize.