Slipping out of Lincoln Center last week, the conductor of the American Ballet Theater, David LaMarche, fell in with a crowd heading into the subway at 66th Street. To his surprise, a familiar flute melody was wafting up the stairs.

It was from “La Bayadère,” the ballet he had just finished conducting.

“You hear the music day in and day out,” Mr. LaMarche said. “Then you go into subway, and this guy is playing it. … I think it’s amazing how he does it. He really is paying attention.”

The musician is Martin Jennings, 47. With his wine-colored velvet blazer, striped lavender tie, and flute or saxophone in hand, he is a fixture in the station.

Using season schedules from the ballet, opera, and the philharmonic, Mr. Jennings each week orders sheet music, CDs, and DVDs of performances from the New York Public Library. During the day he studies and practices at his Upper West Side apartment, and nearly every night he sets up his music stand about 30 feet from the entrance to the subway and plays for money.

“What I do is kind of humble comparatively,” Mr. Jennings said in an interview, calling the Lincoln Center performances “luxurious and exuberant shows of considerable style and panache.”

When “The Nutcracker” is playing during the winter, some people dance on the platform as he plays, he said, but it doesn’t last. Every few minutes the audience is either shuttled off or interrupted by the no. 2 and 3 trains that rattle through the station.

Another distraction: A Gambian man playing a 21-string instrument called the kora lately has been slowly moving down from the north entrance of the station.

“When you go into a theater, it’s very calm; there is a potential for gentleness, contrast, aggression, or drama,” he said. “I’m being slammed by the noise of express trains.”

There have been admirers over the past five years he has been playing at 66th Street, including actor Ethan Hawke, who dropped him $5 when he was performing in “Coast of Utopia.” Still, Mr. Jennings said he has his sights aimed higher. At home he has a collection of “partly begun pieces, of a grand scale,” but says he can’t find the time to finish most of them.

Mr. Jennings was born to a musical family in the north of Manchester. His mother was a violinist in the Royal Liverpool Philharmonic Orchestra and his father was a dedicated fan of Charlie Parker Jr., the Missouri-bred jazz legend known as “Bird.” As a child, he studied music and eventually went to the Guild Hall School of Music, also in Manchester.

“Things went wrong there,” Mr. Jennings said. “I started getting into jazz music. I kind of started experimenting and went off the rails, really.”

Then his parents got divorced and he went through an emotional break-up with the mother of his child, who was given up for adoption. He found solace in long-distance cycling, a habit he has taken up again in New York. He traveled Europe.

Ten years ago, he moved to the city permanently.

A chance encounter in Central Park with a musician and emergency internist, Ronald “Doc” Jones, led him to join a band, “Doc Jones and the Medicine Men,” where he played alongside Coleridge-Taylor Perkinson, an arranger and pianist who died in 2004.

“Marty is a genius,” Dr. Jones said. “He can play music with a British accent.”

During one of Mr. Jennings’s performances at 66th Street on Friday night, a group of women dressed up for a night at the ballet seemed to recognize the music and smile, already nostalgic 10 minutes after the performance. Others did not seem to notice, and a short man began playing a wooden flute as he walked past, oblivious to the effort.

“Sure, I really want much more than this,” Mr. Jennings said. “But I am working with what I know.”