In 2009, Yannatos retired from directing HRO, which celebrated its 200th anniversary the year before. But Yannatos did not retire his support for the Harvard-Radcliffe Orchestra.

In a meeting to pass his baton to current director Federico Cortese, Yannatos, Cortese recalled, said in an affectionate tone: “You will love this job.”

“It meant a great deal to him to share his love of music,” said Nyia Yannatos, his wife. “He felt it was part of his mission as a teacher to pass that on.”

Nyia said that Yannatos was delighted at the start of each term to see how the orchestra would come together from the previous year.

“He cared about you as a musician and how you were going to grow as a person after you left Harvard,” Victor Lee said.

On the night of his last concert with HRO, Yannatos was awarded an honorary certificate for his decades of contributions to the orchestra. The certificate declared Harvard’s gratitude to how Yannatos “enhanced the cultural life of Harvard University” while “enriching the lives of thousands” with his music knowledge, artistry, and passion.

Yannatos was not only a conductor and instructor, but also a violinist and a composer.

In 1971, he wrote an opera titled “Rockets’ Red Blare,” which premiered at Harvard as a student production.

On Oct. 1 and 2, 2011, Intermezzo, the New England Chamber Opera Series, performed his rewritten score to “Rockets’ Red Blare” in a professional debut at the Agassiz Theater, which Yannatos attended.

“He died with his founding awareness, humor, courage, love, and profound grace, and peacefully,” his daughter Kayla wrote in an obituary for her father.

Yannatos is survived by his wife Nyia, daughter Kayla, and son Dion.

A public memorial service will be held on Dec. 10 at 3 p.m. in Sanders Theatre.

—Hana N. Rouse contributed reporting for this story.

—Staff writer Xi Yu can be reached at xyu@college.harvard.edu.