Eva Coutaz, who in more than four decades at the highly respected record label Harmonia Mundi shaped musicians’ careers, rehabilitated forgotten composers and expanded the tastes of record collectors, died on Jan. 26 in Arles, France. She was 77.

Jean-Marc Berns, the label’s head of marketing, said the cause was complications of renal failure.

Ms. Coutaz joined Harmonia Mundi in 1972 at the invitation of its founder, Bernard Coutaz, whom she would go on to marry. Her first job was to oversee publicity and to organize concerts to promote the label’s artists, but she quickly proved her business acumen and artistic sensibility.

Ms. Coutaz nurtured long-term relationships with a stable of musicians that included some of the leading figures in early music, among them the countertenor Alfred Deller and the performer-conductors René Jacobs, William Christie and Philippe Herreweghe. Later she brought in another generation of recording stars, including the violinist Isabelle Faust, the pianist Alexandre Tharaud and the baritone Matthias Goerne.

She built a catalog of more than 800 recordings as head of production starting in 1975. On the death of her husband in 2010 she became chief executive of the company and remained in that post until 2015, when she sold the label.

At its most prolific, Harmonia Mundi released more than 50 new recordings a year. Industry publications frequently crowned it label of the year, and collectors came to trust it as a guide to hidden gems and illuminating interpretations of the classics. With their beautifully designed covers and thoughtful liner notes, Harmonia Mundi albums stood for a listening culture that was both meticulous and meditative.

Ms. Coutaz was “the great guiding force” behind the label, Mr. Christie said in a phone interview. As a businesswoman, he said, she could be “tough as old boots.”

“She had a strong will and an extraordinary sense of rightness about repertory,” he added. “And she was going to take risks.”

In the 1970s and ’80s, those risks paid handsome dividends in a market buoyed by fresh interest in early music and historically informed interpretations. Ms. Coutaz recognized, for example, the market potential of the French baroque composer Marc-Antoine Charpentier at a time when his ilk lagged far behind the popular appeal of their German and Italian counterparts, Mr. Christie said.

Costly productions of unknown oratorios and operas remained a gamble, and Ms. Coutaz greenlighted some projects against her own better financial judgment. In a 2018 radio interview with the Belgian station RTBF, she spoke about a recording, led by Mr. Jacobs, of the opera “Croesus” by the northern German baroque composer Reinhard Keiser — a footnote in music history books.

“I thought it would be a loss for us,” she said. But she was so taken by the music that she told herself, “I want to record it — it would be a shame if people don’t hear it.” “Croesus” sold more than 25,000 copies, a triumph for classical music.

Mr. Jacobs said that Ms. Coutaz had encouraged his conducting career when he was still known mainly as a countertenor. After he had gained fame as a champion of Baroque music, she urged him to record Mozart operas. His Harmonia Mundi recording of Mozart’s “Le Nozze di Figaro” won a Grammy Award in 2004 and became a best seller.

“She pushed me to go further,” he said.

Eva Schannath was born in Wuppertal, Germany, on Feb. 26, 1943. Her father was a cabinetmaker. After attending a Roman Catholic school in Düsseldorf, she took on an apprenticeship as a bookseller. Eager to experience France, she went to Marseille in 1964 as an au pair, then stayed on, working first at a book shop in Montpellier and then for a cultural center in Aix-en-Provence.

It was there, in 1972, that she met Mr. Coutaz, who was then running Harmonia Mundi from Saint-Michel-l’Observatoire, a remote village in Provence. Mr. Coutaz founded the company in 1958.

Jean-Guihen Queyras, a boy studying the cello, was living in a nearby hamlet, and his parents befriended the couple. When he was 10 he received his first taste of a Harmonia Mundi recording session when Ms. Coutaz invited him to work the organ bellows for Mr. Christie in a tiny Romanesque mountain chapel.

Years later Mr. Queyras joined the label as a soloist. “What was different to other labels was her vision and her very human and organic way to bring together musicians in a way that really feels like a family,” he said.

He recalled her strong emotional reactions to music. “Sometimes she would talk to you after a concert, and you could see there had been tears,” he said. “She really made all this out of pure, intense love for music.”

Eva and Bernard Coutaz worked closely together even as they married, divorced and remarried. They had no children. Information on her survivors was not immediately available.

The couple moved the label to an old farmhouse in Arles in 1986. It became the creative and logistical hub for a company that at its height employed more than 350 people. Its influence spread through subsidiaries in Spain and the United States, a publishing arm and a network of record boutiques.

In the early 2000s, the rise of streaming started to put the recording industry in crisis and forced painful cuts at Harmonia Mundi. In the radio interview, Ms. Coutaz spoke of a 70 percent drop in CD sales over a span of 10 years. She warned that as earnings plummeted, high-quality studio recordings would become a thing of the past. “If digital sales are not monetized, the moment will come when you can no longer produce,” she said.

In 2015, she approved the sale of Harmonia Mundi’s catalog to PIAS, a Belgian group of independent labels. She remained involved as a consultant for another year, to help maintain quality. In 2018, Gramophone, a leading classical music publication, named Harmonia Mundi label of the year.

Reflecting on Ms. Coutaz, Mr. Christie said his generation had known a recording industry led by “strong-minded and intensely committed individuals who had an extraordinary sense of the rightness of what they were doing and how to create markets.”

“And she stood out among them.”