Stanislaw Skrowaczewski, 93, best known as music director of the Minnesota Orchestra in the 1960s and '70s and guest conductor of major orchestras internationally, died Tuesday, Feb. 21, in Minneapolis, his agent announced.

The Polish-born conductor and composer was a regular presence with the Philadelphia Orchestra and led more than 100 concerts by the Philadelphians between 1964 and 1992, here, across the U.S., and on international tours.

He and they worked with major artists – Benny Goodman, Marian Anderson, and Van Cliburn in Saratoga Springs, N.Y.; Metropolitan Opera stars Richard Tucker and Robert Merrill at the old Robin Hood Dell; pianists Rudolf Firkušný in Ann Arbor, Mich., and Alexis Weissenberg at Carnegie Hall; and Isaac Stern at the Mann Center and at the Academy of Music 133rd Anniversary Concert and Ball.

He was also a composer, a rare doubling for a conductor, and was the Philadelphia Orchestra's composer in residence in 1988 at the Saratoga Performing Arts Center.

"There is barely a handful of composers of such excellence who are also great conductors, as he was," said the pianist Garrick Ohlsson, who worked with him often starting in 1971 and until 2015 with orchestras in Europe, North America, and Japan. "He was always in search of the ineffable, of the infinite, in music. He was never self-congratulatory, but always sought consciously and vigorously to make the next performance better, even in a run of repeated concerts."

Ohlsson said Mr. Skrowaczewski always put the composer's wishes first. "Sometimes this meant introducing small changes in orchestration, never to 'improve' something, but to make it clear," he said. "When I played the Chopin concertos with him, once he didn't make a change in the scoring he had made the previous time, and I asked him about it. He replied that in this hall, with this orchestra, the change wasn't necessary, as it sounded well and clear, as the score indicated."

Mr. Skrowaczewski, often known as "Stan," led the Philadelphia Orchestra on tours to South America in 1966, the United States and Mexico in 1980, and often to the orchestra's summer homes in Philadelphia and Saratoga Springs. "We are very much a family," Skrowaczewski told the Inquirer in 1988. "They are such special people, so friendly and open. I can hardly think of any other [players] who are this open. They are not arrogant, like great musicians can be. "

His Violin Concerto was written for the Philadelphia Orchestra and was debuted in 1985 by then-concertmaster Norman Carol to mark 20 years with the orchestra, after being commissioned by the orchestra's Old York Road Committee of volunteers. "For all the dissonance and rhythmic complexity in the score, its transparency is the guiding principle," wrote an Inquirer critic of the first performance. "The work makes the violin sound larger than life because the surrounding textures are so clear and unusual."

Mr. Skrowaczewski also guest conducted the Curtis Institute of Music's orchestra on occasion, including the world premiere of his Concerto Nicolò for left-hand piano with Gary Graffman and the Curtis orchestra in 2003, and a 1998 concert with his Concerto for Orchestra and violinist Juliette Kang in the Prokofiev Violin Concerto No. 1. Kang, a Curtis alumna who had not yet joined the Philadelphia Orchestra at the time, remembered the conductor as "very generous and supportive. The performance and rehearsal experience both felt totally natural, not overly talked through, and at a small dinner party afterward he was very humble and down to earth, a complete gentleman."

Born in Lwów – then in Poland, now in Ukraine – Mr. Skrowaczewski was a pianist first. He sustained a hand injury from a bomb explosion during the Nazi assault on Lwów in 1941, ending his keyboard career and moving him toward composing and conducting. He attended the Academy of Music in Kraków, and then studied with Nadia Boulanger in Paris.

In 1958, he was invited to the United States to conduct the Cleveland Orchestra, and became music director in Minneapolis in 1960. He kept that post until 1979, but kept a close relationship with the orchestra.

"He understood how to create breadth of time and space to give scale and volume to music, to craft the arch of the line as though he were a master stone cutter working in great slabs of granite," said Jorja Fleezanis, Minnesota Orchestra concertmaster for two decades starting in 1989 while Mr. Skrowaczewski continued as laureate conductor. "And as a man who understood and lived through one of the tragic chapters wrought on humankind, he could move an entire orchestra to utter the unspeakable horrors within the darkest moments of a work and lead them forward to exaltation and the sublime."

Ohlsson traced the conductor's mastery of scores to his work as a composer. "He understood the complex network of the literal text, phrasing, harmonic rhythm, metric and phrase accents, dynamic relationships, balance/acoustics, and the real musicians in front of him," he said. "Of course, every great conductor does this in his or her own way, and Stan's way was often most memorable. I'll never forget  his Schumann Fourth, Bruckner Seventh, Shostakovich Fifth, and so much else."

During his long career, he led the Royal Concertgebouw, London Symphony, Chicago Symphony, Boston Symphony, Munich Philharmonic, and the Vienna and Berlin Philharmonics.

He continued to conduct until recently. A Beethoven Seventh he conducted in 2015 Ohlsson described as "on fire. Remarkable."

He is survived by sons Paul and Nicholas, and daughter Anna. His wife, Krystyna Emma Jarosz, died in 2011.

A celebration of his life is scheduled for Tuesday, March 28, at Orchestra Hall in Minneapolis.