Sills died of cancer last week, at 78. Through formidable vocal and dramatic gifts, irrepressible humor and a will of titanium, she changed the face of opera in America. A frequent, hilarious guest on Johnny Carson’s “Tonight Show,” she wanted people to know “that opera singers don’t have horns.”

At 4, she was already singing on the radio. She began vocal studies at 7, and stayed with the same teacher for more than 30 years. The cornerstones of her vocal production were flexibility and breath control. At her peak in the 1960s and 1970s, she could float passages over a full orchestra; she could sing long runs in which each individual note was clear but which ran down a listener’s back like melted chocolate. She had a trill that could wind a clock, and could color her voice from shimmering silver to dark red.

What set Sills apart was her insistence on the marriage of text and music. Her Lucia was off-the-charts mad; her Manon seduced not just a priest but 3,000 people in the theater. Sills’s rock-solid technique made it possible for her to take on heavy roles. And if singing a fiendishly demanding part such as Queen Elizabeth I in Donizetti’s “Roberto Devereux” cut a few years off her career, so be it. She was a risk taker: in Rimsky-Korsakov’s “Le Coq d’or,” she wore a harem outfit while doing a belly dance. “I figured a moving target was safest,” she said. There were singers with bigger, steelier voices, but in her combination of talents and in her range of repertoire, she was just about peerless.

Her personal life was less triumphant. She was happily married to Peter Greenough, a former newspaper columnist who died last year, but their daughter was born deaf and their son is severely autistic. Before the births of her children, Sills was a good singer; afterward, she was electrifying. Her only worry-free moments, she said, were when she was onstage.

She never really left it. After performing with the New York City Opera for 25 years, she ran the company for an additional 10, then became chairwoman of Lincoln Center for the Performing Arts and, after that, chairwoman of the Metropolitan Opera. Until her death, she was a commentator on the Met’s broadcasts and telecasts; the company’s $50,000 annual prize to a young singer is the Beverly Sills Artist Award. “The arts are the signature of a civilization,” she often said, exhorting everyone to write a check. (She was a legendary fund-raiser, not just for the New York City Opera and the Met, but for the Mother’s March on Birth Defects and for the Multiple Sclerosis Society.)

Sills always ended her recitals with a folk song that she learned, at 10, from her teacher. “Time has come for me to leave you,” she sang. “You’ll be forever in my heart.” And you in ours, Beverly.