LOS ANGELES — When Los Angeles Philharmonic violinist Vijay Gupta won a MacArthur fellowship this year for his social justice work, an award that came with a $625,000 no-strings-attached stipend, the obvious question was: What next?

The answer: Gupta said that he will give up his seat as one of the orchestra’s first violins to focus on his activism, to teach and to develop his nonprofit Street Symphony, which since 2011 has been performing free concerts for Los Angeles’ homeless and in county jails.

Gupta, who joined the orchestra as a teenager in 2007 and was its youngest musician, said he’s also looking forward to “just having time to rest and reflect.”

“I feel like the L.A. Phil saved my life when I was a 19-year-old kid. It was the way that I was able to continue being a musician and to continue growing as an artist” he said. “And I’m really excited to take that artistry beyond Los Angeles and beyond the work of being in an orchestra.”

Gupta, 31, is creating part-time operations and management positions at Street Symphony. The nonprofit is moving from Gupta’s living room into its first office, a downtown space it will share with the homeless advocacy and performance group Los Angeles Poverty Department. He’s also hoping to expand its fellows program, in which skid row musicians study for up to a year with professional musicians.

The idea, he said, is “to shore up the infrastructure of the organization so that Street Symphony can grow and flourish beyond Vijay Gupta.”

Starting in January, Gupta will be a guest lecturer at the Juilliard School in New York. And he hopes to continue teaching his class at L.A.’s Colburn School.