Fred Hersch’s lyrical piano musings place him among the top jazz musicians at his instrument in annual polls—and he’s earned 10 Grammy nominations. He’ll likely have a shot at another with his next solo album of originals and standards, Open Book, which won’t be his only eagerly awaited release this September.

The pianist will open up in an actual book with the Sept. 12 publication of his memoir, Good Things Happen Slowly: A Life In and Out of Jazz. The idea grew out of an interview with the Bad Plus pianist Ethan Iverson, his former private student (Hersch also taught at his alma mater New England Conservatory from 1980 to 2015).

“Ethan was very interested in what it was like in the late ’70s when I first came to New York,” says Hersch, 61. “I wanted to write a book that even if you weren’t a jazz head, there were other things you could get out of it. Of course, I’ve had a lot of drama with my personal life and my health, so that was part of it.”

Hersch learned he was HIV-positive in the ’80s. In 2008, he suffered AIDS-related dementia and grew gravely ill from pneumonia. Hersch was put into an induced coma for two months, and when he regained consciousness, he couldn’t even hold a pencil.

“I realized my life as I knew it was gone,” Hersch says, adding that he couldn’t walk, stand, talk or even eat. “I weighed less than 100 pounds. I couldn’t move my arms very well. I was just determined that I was going to get myself back together.”

He has—and then some. Hersch has received perhaps his greatest acclaim during the past several years. “I do feel like I’m playing better than ever,” says the pianist, who’ll bring his simpatico longtime trio with bassist John Hebert and drummer Eric McPherson to play the Rockport Jazz Festival at the Shalin Liu Performance Center on Aug. 10.

“When you go through something that’s life-changing, obviously you come out the other side different,” he says. “In my case, it was a motivator, and it was also the sense of ‘Well, I’ve been through the worst of it, so if I play a chord that I don’t like, it’s not a tragedy.’ You don’t get bent around the small stuff as much.”

Hersch was more easily flustered in his youth, navigating both his music and sexuality. “There weren’t people who were out, who were in Hollywood or on TV,” he says. “When you’re young, you think you’re the only person that way.”

He kept his secret in the largely closeted jazz world as well—to a point. “I was the one who just said ‘Screw it’ and broke the mold and talked about not just being a gay jazz musician, but dealing with HIV,” he says. “I thought maybe I could help some people along the line and make it easier for them. I didn’t expect to be an activist, but I kind of ended up being one… I said, ‘OK, I don’t even know how much longer I’m going to be alive, so why hold back?’ ”

The same went for his playing. Hersch pioneered an impressionistic brand of jazz that drew from pop, classical and Brazilian influences, exploring the emotional layers of songs beyond mere technical facility. It paid off in the long run. He ties the title of his memoir (coined from a comment a doctor made during his coma) to his career as well.

“I was kind of a prodigy,” says Hersch, who worked with jazz greats Art Farmer and Joe Henderson early on and played at New York musicians’ haunt Bradley’s, introducing himself to patrons Charles Mingus and Joni Mitchell. “But I was passed over by the whole young-lion movement, and I’ve always been a little different, not quite what [record companies] are looking for in terms of branding and packaging. Maybe it’s a testament to sticking to what I do.” ♦

The Fred Hersch Trio plays Rockport’s Shalin Liu Performance Center on Aug. 10.