Seymour Bernstein, the great classical pianist, quit the stage in 1977, deciding that a recital at the 92nd St Y in New York City would be his farewell – though he didn’t tell anyone of his decision. He didn’t return to the stage until last year, when actor Ethan Hawke asked him to play a small concert as a grand gesture for a documentary Hawke was directing about the now 87-year-old piano teacher, called Seymour: An Introduction.

“Why did I decide to play the recital at the end of the movie? Because he asked me,” Bernstein tells the Guardian. “I wouldn’t have turned him down for the world.”

Hawke and Bernstein struck up a friendship at a dinner party hosted by one of Bernstein’s pupils. Something in their conversation struck a chord with Hawke, who had been struggling with late-onset stage fright. “I had been dealing with a lot of my own issues about anxiety and performance that were starting to seem like a real crisis in my life,” says Hawke. “When I met Seymour, I saw someone who had devoted his life to the arts and was brimming with joy and bristling with creativity, and energy, and hopefulness.”

For Hawke, Bernstein was not only a new friend but a mentor, a fellow performer who had navigated the rocky road of performance anxiety and come out happier. “I see so many people in the arts who are beaten down by either success or failure,” says Hawke. “I didn’t want that. I wanted to be hopeful.” He found that hope in conversation – and kinship – with Bernstein and decided to help share Bernstein’s insight with the world through a film, the first Hawke has directed.

“The film is about Seymour, it’s about his beliefs and his message,” says Hawke. “Some of the things that Seymour speaks about were things that I had never heard before.” So the two friends – who clearly share a deep respect for each other, happily interrupting one other and laughing throughout the interview – set out over the course of two years of sporadic filming to make a documentary.

“It’s so fun to lay yourself bare,” says Hawke. “I had no idea what I was doing. I knew I wanted to make this documentary. I knew that [Seymour] was a worthy subject. But I had never made a documentary before and [he] had never been in one. We were both at this absolute starting place. And that feels so good.”

“That didn’t feel good to me,” interjects Bernstein. “I was scared out of my wits the first time.” Bernstein, who left his stage career partially due to nerves, said that the first time the cameras were rolling, “I blacked out.” He persevered with the project, though, and by the third day of filming he was comfortable in front of the camera.

That perseverance is central to the film’s theme, which is as much the story of Bernstein as a meditation on art and the practice of craft. “The film opens with me at my piano, practicing a Scarlatti piece, and I kept missing a leap – that was already a struggle. It wasn’t staged, it was a real, live moment of a pianist practicing,” said Bernstein. “Do you know what that does to a person? One moment you can’t do something and through the effort – the struggle – you find out how you can survive that particular challenge. You get a rush of pride and a love for yourself. Parents get that with their children. Teachers get that with their pupils. What a rush!”

“The struggle is everything,” confirmed Hawke. “The struggle makes everything.”

In the film, Bernstein continually points out how important it is for people to hone their craft, despite their anxiety. “Nervousness is part of what we do,” he says in the film, offering up an anecdote where actress Sarah Bernhardt tells a young upstart: “You will get nervous when you learn how to act.”

However, Hawke did his best to make sure that the subject of his documentary was at ease. Instead of having Bernstein narrate the film as a monologue or cast himself as an off-camera interviewer, Hawke conscripted Bernstein’s friends and pupils to interview him on camera and act as the audience’s proxy.

“Everybody had different jobs to do to help tell the story about what [Seymour’s] teaching is about,” said Hawke.

For instance, New York Times critic Michael Kimmelman, a former student of Bernstein’s, chats with him during the film, while the cameras roll. “Michael could be the one to put Seymour on the spot a little bit, and make him answer why he quit performing,” said Hawke. “I could have had a whole documentary about that conversation. It was amazing.”

One of the themes of many of those conversations is the role of the artist in society. When Hawke mentions artists who have struggled under the weight of success or failure, Bernstein seemingly brushes them off. (In the film the late pianist Glenn Gould is dismissed as “a total neurotic mess”.)

“Mostly those people who are unfocused and neurotic; they can be great artists, but they are doing it for the wrong reasons. They are doing it for self-aggrandizement or to make money or because they don’t know what else to do,” said Bernstein. “They have no idea that they are emissaries for the greatest minds the composers and the writers – what a responsibility it is, what a privilege it is.”