Reinbert de Leeuw, a Dutch conductor pianist and composer who advocated — sometimes raucously — for contemporary music in his homeland, enjoyed productive associations with the Los Angeles Philharmonic, the Sydney Symphony and the Chamber Music Society of Lincoln Center, and had a memorable stint at the Tanglewood Festival, died on Feb. 14 at his home in Amsterdam. He was 81.
Though Mr. de Leeuw was not the kind of big-name maestro who frequents the international guest-conductor circuit, he brought crucial attention to contemporary music by working with smaller ensembles, directing festivals and advising major institutions.
He was an influential figure in the Netherlands, where he conducted in important productions of contemporary operas by Gyorgy Ligeti, Claude Vivier and his countryman Louis Andriessen, and led performances of ambitious scores by Schoenberg and Messiaen.
Mr. de Leeuw first came to wide notice as a pianist, with exemplary performances and acclaimed recordings of works by Bartok, Stravinsky, Shostakovich and Messiaen.
His 1981 three-disc album of Erik Satie’s early piano works drew attention to this overlooked music, which he performed with elegant restraint and directness, bravely observing the very slow tempo indications in many of these scores to haunting effect.
On the podium, Mr. de Leeuw, a small-framed and soft-spoken man, could galvanize performances of complex contemporary operas and orchestral works involving large forces.
In 1999, at Alice Tully Hall in New York, he led a triumphant performance of Messiaen’s teeming, brassy and ecstatic “Des Canyons aux Étoiles …” (“From the Canyons to the Stars…”), a 100-minute piece from 1974. Presented by the Chamber Music Society of Lincoln Center, the performance featured Peter Serkin in the daunting solo piano part. (Mr. Serkin died this month.)
Messiaen was inspired to write the work by a trip to Bryce Canyon National Park and Cedar Breaks National Monument in Utah.
The next year, Mr. de Leeuw led a small cast of soloists, as well as members of the Dutch National Opera and the players of the Asko and Schönberg Ensembles, in the United States premiere of Mr. Andriessen’s opera “Writing to Vermeer,” co-directed by Peter Greenaway, who wrote the libretto.
The work imagines the life of the painter, who is away on a trip, as conveyed through letters to him from his pregnant wife, mother-in-law and favorite model, all sent from the city of Delft in a time of war, violence and floods in the Netherlands.
Critics were divided over this massive production, which opened the 2000 Lincoln Center Festival. However, Mr. de Leeuw’s conducting of this wondrous score — a mash of styles, colors and intricate textures — was a revelation. (He later recorded the opera on the Nonesuch label.)
Mr. de Leeuw’s sensitivity as a musician perhaps came through best in intimate settings, including a pair of recitals he presented in 2017 with the adventurous soprano Barbara Hannigan in the Board of Officers Room at the Park Avenue Armory in Manhattan.
The first recital offered songs by composers of the Second Viennese School, including Schönberg, Berg and Webern; the second featured works by Satie, including the composer’s subdued and alluring “Socrate.” In an interview with The New York Times, Ms. Hannigan gave Mr. de Leeuw full credit for conceiving the project and boosting her courage to take it on.
“He just said, ‘I have a recital program for us,’ and that was it,” Ms. Hannigan said. “If it’s with Reinbert, I’ll do it.”
Lambertus Reinier de Leeuw was born on Sept. 8, 1938, in Amsterdam. His parents, Cornelis Homme de Leeuw and Adriana Judina Aalbers, were both psychiatrists.
Reinbert, as he was known, had a troubled youth, as Thea Derks, a Dutch music journalist, recounted in her 2014 biography of him. His hardworking parents, seldom at home, were not “cuddly types,” Ms. Derks said in a recent email. So Reinbert was cared for by a succession of housekeepers.
His father, who suffered from depression, died in 1953; his mother died of cancer in 1957. Mr. de Leeuw wound up living with his mother’s sister.
His focus on music came relatively late. After studying Dutch literature at the University of Amsterdam for two years, he entered the city’s conservatory to study music theory, earning his piano diploma in 1964. His regard for maverick composers from all countries led to his writing, with J. Bernlef, a biography of Charles Ives, published in the Netherlands in 1969.
From the start, Mr. de Leeuw’s work as a pianist, composer and conductor went hand in hand with his campaign to persuade Amsterdam’s eminent Concertgebouw Orchestra to include more new music in its programming.
In 1969, as part of what was called the Nutcracker’s Action Group, he and fellow agitators, including Mr. Andriessen, disrupted a concert in the orchestra’s fabled hall by making noise with nutcrackers, rattles, bicycle horns and such. They passed out leaflets denouncing the orchestra as a status symbol of the elite. The protesters were ejected, but their campaign, and values, began to take hold.
During these years Mr. de Leeuw became a member, then chairman, of the Amsterdam Arts Council. He founded the Schönberg Ensemble in 1974 to champion works by composers of the Second Viennese School as well as newer avant-garde music. His group collaborated often with the Asko Ensemble, which gave concerts and took part in film, dance and operatic projects. The ensembles merged in 2008, with Mr. de Leeuw as director.
As he spent more time performing — and, over time, teaching, including at the University of Leiden — he focused less on composing. His small catalog of original works, mostly from the 1960s and ’70s, includes a string quartet and the orchestral pieces “Interplay” and “Abschied.”
In 1992 Mr. de Leeuw was the guest artistic director of the prestigious Aldeburgh Festival in England. From 1994 to 1998 he was the director of the Tanglewood Festival of Contemporary Music.
During the 1995 festival, as the critic Allan Kozinn wrote in The Times, Mr. de Leeuw introduced “the most varied survey of new music ever offered at Tanglewood.”
Unconcerned with “festival politics,” Mr. Kozinn added, Mr. de Leeuw presented styles of contemporary music that had been “either actively disliked or simply overlooked” by his predecessors in the post.
Mr. de Leeuw declared his all-embracing philosophy in the 1995 program booklet. The ambition of approaching contemporary music “with a universal language comparable to the language of tonality has failed,” he wrote. It was no longer feasible, he continued, to distinguish between musically “correct” and “incorrect” camps. Rather, he said, it was essential to understand the “complexity and variety of the music of our century.”
Mr. de Leeuw is survived by two brothers, Kees and Hans de Leeuw.
Last year, in an interview with NRC, a Dutch newspaper, he fretted that “we have not been sufficiently able to defend” Amsterdam’s musical life, worrying that entire areas of 20th-century music were in danger of disappearing.
Mr. de Leeuw did not disagree with the suggestion that he had lived almost like a monk in the service of music. “You can live your life in countless ways,” he said. “This is mine.”