Christopher Rouse, a Pulitzer Prize-winning composer known for unpredictable, expressionistic works that immersed listeners in a world of anguish, terror and sensuous beauty, died Sept. 21 at a hospice center in Towson, Maryland. He was 70.

The cause was complications of renal cancer, said Carol Ann Cheung, a publicist with his music publisher, Boosey & Hawkes. Rouse’s final work, Symphony No. 6, is scheduled to premiere Oct. 18 with the Cincinnati Symphony Orchestra and conductor Louis Langrée.

As recently as last week, Rouse was still polishing the score, according to his friend Joel Puckett, a composer who taught alongside Rouse at the Peabody Institute of Johns Hopkins University. “Even at the very end, he was assessing the moves and structures and tricks he’s used before, still trying to find new ways to crack the nut,” Puckett said.

Rare among modern composers for achieving both critical acclaim and popular success, Rouse wrote chamber and vocal works that were performed around the world and taught for more than two decades at the Eastman School of Music in Rochester, New York. But he was best known for his symphonies and concertos, which featured a sound that cellist Yo-Yo Ma once described as “spiritual without being sentimental, deeply felt without sentimentality.”

Trained in the 1960s and ’70s, an era of heady experimentation in classical music, Rouse drew on the 12-tone serialism taught by his professor Richard Hoffmann, the neoclassical principles of pianist Robert Palmer, the rigorous formalism of composer Karel Husa and the avant-garde instrumentation of his private instructor, George Crumb.

But he broke with many of his mentors and peers in his love for the Romantic tradition of composers such as Johannes Brahms and Dmitri Shostakovich, and for his use of electric guitars and rock motifs. He quoted the rock bands Jefferson Airplane and Moby Grape and made headlines for his eight-person percussion piece “Bonham” (1988), written as an ode to Led Zeppelin drummer John Bonham.

In hard-rock fashion, some of his scores were so loud that fortissimo was said to be marked with six F’s, instead of the usual two. That boisterousness contributed to a 1985 incident in which a member of the Indianapolis Symphony Orchestra, where Rouse was a composer in residence, filed a complaint with the Occupational Safety and Health Administration, saying his music was too loud.

“To me, loud dynamics have to do with expressive urgency,” Rouse once told The Baltimore Sun. “What’s important is what music conveys and how it’s meaningful to the human spirit. If one has something urgent to say, intense emotions are usually lined up with loud dynamics. Part of being a human being is a need to beat one’s breast – to shout or scream.”

In 1993, Rouse won the Pulitzer Prize in music for his Trombone Concerto, which he described as one of his “softer” pieces. When it premiered at the New York Philharmonic the previous year, some of the string musicians were seen putting their fingers in their ears onstage; New York Times music critic Edward Rothstein said he had “never heard the orchestra play louder.”

“The trombone, an instrument typically associated with slides and energy and swing, with sudden moves and blasts, is here turned into an almost introspective isolate: lyrically mourning, then raging and mourning again,” Rothstein wrote. The concerto featured “an element of risk,” he added, “as if something personal were being revealed. At its best, the music can seem a form of expressionist soul-baring.”

Trombone Concerto was dedicated to composer and conductor Leonard Bernstein, who died in 1990, and was the first of several major works by Rouse concerned with death. The theme had interested him since at least the age of 8, when his best friend hanged himself, according to The Sun. For a Cub Scout project that year, Rouse reportedly wrote that he would grow up to “be famous for a darkness of sickness” and “be a great American composer.”

By all accounts, Rouse was far from dour – “man does not live by dread alone,” he quipped – and said he kept writing about death simply because friends and family kept dying. In 1992, he completed his Violoncello Concerto, a memorial to the late composers William Schuman and Andrzej Panufnik.

“The second movement is about the last nanosecond of life, the moment when you are no longer alive but not quite dead,” he told the Boston Globe. “It is not a consoling piece,” he added.

Earning the ironic nickname “Mr. Sunshine,” Rouse went on to write Flute Concerto (1993) dedicated to slain toddler James Bulger; Symphony No. 2 (1994), which featured an adagio in memory of composer Stephen Albert, who died in a car crash; and “Envoi” (1995), an orchestral work dedicated to his late mother. In the aftermath of the Sept. 11, 2001, terrorist attacks, he completed an apocalyptic, 90-minute Requiem (2002).

Beginning in the mid-1990s, Rouse moved toward lighter material such as “Concert de Gaudí,” inspired by the phantasmagoric work of Spanish architect Antoni Gaudí. Rouse won a Grammy Award after it was recorded by Sharon Isbin.

He also continued to focus on his teaching, offering one of the first music-school courses on rock history and advising young composers such as Kamran Ince and Nico Muhly to “just listen to everything,” whether contemporary or canonical.

“If he thought you were any good at all, he was going to tell you something horrible about your music,” his colleague Puckett said by phone, recalling Rouse’s tough-love approach. “He was also hard on himself. I asked him once, ‘Do you have a favorite piece of yours?’ He said, ‘The Flute Concerto is almost good enough for me to be proud of.’ And I’ve listened to that piece maybe 1,000 times in the last 20 years. It’s just heartbreakingly beautiful.”

Christopher Chapman Rouse III was born in Baltimore on Feb. 15, 1949. His father worked in sales at Pitney Bowes, the postage meter company. His mother was a secretary who introduced Rouse to classical music, playing Beethoven’s Fifth Symphony on the record player.

He soon decided to become a composer but never mastered an instrument, lasting six months on percussion. He also never wrote things down: For his application to the Oberlin Conservatory of Music in Ohio, he composed a piece he misleadingly titled Symphony No. 2, “so that it would look like I’d been busy.”

Rouse graduated from Oberlin with a bachelor’s degree in 1971 and received a doctorate in music from Cornell University in 1977. He began teaching at Eastman in 1981 and also taught at institutions including the Juilliard School in Manhattan and the Aspen Music Festival and School in Colorado.

His notable early compositions included “Bump” (1985), an orchestral work that Rouse described as “my vision of a Boston Pops tour performance in hell,” and Symphony No. 1, which won the 1988 Kennedy Center Friedheim Award for composing.

Rouse’s marriage to Ann Rouse ended in divorce. In 2016, he married Natasha Miller, whose name he encoded into Symphony No. 3 using a system that assigned musical pitches to letters. In addition to his wife, of Baltimore, survivors include two children from his earlier marriage; three stepchildren; and two grandchildren.

For years, Rouse wrote primarily during the summer, when he wasn’t teaching, seated at a card table in his Baltimore living room with little more than a No. 2 pencil and stack of music paper. As he had in his youth, he composed largely inside his own head, marshaling instruments he never learned to play.

“I do not write music just for myself, to provide a personal catharsis,” he told the Globe in 1997. “Music is not about self-fulfillment. Instead, it is a communicative art. I deeply believe in the importance of the audience. Music, like the other arts, has the power to present something meaningful to people about human experience, about their own experiences. . . . Art has to be truthful, not just inspiring. It should always make you sit on the edge of your seat, make you want to live a little more vibrantly.”