Backstage after the curtain calls, Mr. Green greeted some of the people who had helped him get there. There was Betty Hughes, who had taught him in an elementary school class made up of the most troubled children in his district, and who had not given up on him when he hurled his desk in anger on the first day. There was her husband, Leon, who ran the arts high school in Norfolk, Va., where Mr. Green studied singing. And there was Denyce Graves, the mezzo-soprano who sang the title role in the Met performance of “Carmen” that he had heard on that high school trip — his introduction to opera.

“You changed my entire life,” Mr. Green, who now stands 6-foot-5 and has a rich, resonant voice both when he speaks and when he sings, told her.

That Ms. Graves was African-American, like him, had first given Mr. Green the idea that he, too, could sing opera one day. She had received his class warmly when they visited her backstage, in the same room where he was now embracing her.

It was a heady capstone to a major month for Mr. Green. His life story and the new book about it have been featured in recent days by “CBS This Morning,” NPR’s “Fresh Air,” and a range of newspapers including The Washington Post and The New York Post.