On Monday night in University City, a sold-out crowd of Philadelphia cinephiles had the good fortune of previewing Thunder Soul: The True Story of Conrad Johnson & The Kashmere Stage Band at the Rave Theater. The film, a moving and lovingly-executed documentary, tells the story of Conrad “Prof” Johnson and one of the greatest funk ensembles ever assembled, which was comprised of 38 musicians who released 8 records—all while in high school.

From 1968 to 1977, the Kashmere High School Stage Band, nicknamed “The Thunder Soul,” won a record number of titles in numerous competitions, often breaking the color barrier, for their innovative funk arrangements. They made history when they won the top honors at the prestigious All-American High School Stage Band Festival amidst an atmosphere of racial hostility. Johnson’s goal was to use music to raise the morale of the young people he taught at Kashmere High School in Houston, Texas’ Fifth Ward.

Johnson had been a professional musician in the big bands of the 1940s. He was a go-to saxophone player in Houston. After marrying and starting a family, he wanted to stay close to the nest and made a decision to enter teaching. Johnson joined the faculty at Kashmere in the 1960s. He willed the energy of the young people from twiddling their thumbs and getting involved in potential street nonsense and directed them into expressing themselves creatively, which ultimately had a positive effect on the entire school. Training in the band gave the students discipline that they carried with them into their adult lives. When they return to form an alumni ensemble for a reunion concert, they are all thriving and model citizens—doctors, lawyers, and teachers.

Prof recorded the band each year and was a father figure to most members. He had strict discipline and rehearsed them like professional musicians. They played gigs—bar mitzvahs, proms, etc.—to raise the money to keep the program going. They weren’t the marching band. Johnson realized he needed to harness the energy of the kids who would unwind by playing funk tracks instead of practicing the de rigueur rigidly arranged jazz compositions from the 1930s and 1940s. Prof, in his 50s at the time, wondered what this music was that they were playing.

“He was interested in their personal expression,” says Mark Landsman, the film’s director.

Thunder Soul had its premiere at the 2010 SXSW Film Festival. Landsman first heard about the band on NPR after Stones Throw Records released Texas Thunder Soul in 2006. He recalls hearing a “wall of funk” and was blown away. He couldn’t believe they were high school students and set out to find them. Landsman googled every Conrad Johnson he could find and started calling them. The first one he called turned out to be Prof’s son. Initially he thought about a fictional film until he heard about the reunion that was being planned by some of his former students. Over 30 of the students come back to Houston 35 years later, from all over the world, and reunite to do a tribute concert. Still fly at 92 years old when the film was shot in 2008, Johnson appears beatific and sanguine and one can almost feel the love his students have for him.

Oscar-winning actor Jamie Foxx signed on as executive producer in part inspired by his own high school music education. In an interview in the NY Daily News he says that music education played a big part in preparing him for his career.

“It’s a right to have access to music education. It’s part of our national legacy,” Landsman said in an interview with PBS.

At the first rehearsal the band is a bit rusty—will they do it? Will they be able to live up to Prof’s legacy? You have to see the film to find out.

Check out the trailer here.