The pianist Alice Sara Ott, barefoot and wearing a silver bracelet, was smiling and singing to herself the other day as she practiced a jazzy passage of Ravel at Steinway Hall in Midtown Manhattan. A Nintendo Switch, which she uses to warm up her hands, was by her side (another favored tool is a Rubik’s Cube). A shot of espresso sat untouched on the floor.

“I feel I have finally found my voice,” Ott said during a break. “I feel I can finally be myself.”

Ott, 35, who makes her New York Philharmonic debut this week, has built a global career, recording more than a dozen albums and appearing with top ensembles. She has become a force for change in classical music, embracing new approaches (playing Chopin on beat-up pianos in Iceland) and railing against stuffy concert culture (she performs without shoes, finding it more comfortable).

And Ott, who lives in Munich and has roots in Germany and Japan, has done so while grappling with illness. In 2019, when she was 30, she was diagnosed with multiple sclerosis. She says she has not shown any symptoms since starting treatment, but the disorder has made her reflect on the music industry’s grueling work culture.

“I learned to accept that there is a limit and to not go beyond that,” she said. “Everybody knows how to ignore their body and just go on. But there’s always a payback.”

Ott has used her platform to help dispel myths about multiple sclerosis, a disorder of the central nervous system that can cause a wide range of symptoms, including muscle spasms, numbness and vision problems. She has taken to social media to detail her struggles and to challenge those who have suggested that the illness has affected her playing.

She said she felt she had no choice but to be transparent, saying it was important to show that people with multiple sclerosis could lead full lives.

“I don’t consider it as a weakness,” she said. “It’s a fact. I live with it. And I don’t want to make a big drama out of it.”

Ott’s colleagues describe her as an adventurous musician who has helped bring new audiences to classical music with experiments like “Echoes of Life,” a project that blends Chopin preludes with contemporary works, video and Ott’s reflections on life and music.

Bryce Dessner, a composer and a guitarist who wrote a concerto for Ott that she premiered in Zurich this year, said that “what she brings onstage is so specific to her — it’s like she’s unlocking some sort of hidden doorway in each piece that she confronts or interprets.”

The conductor Elim Chan, who performed with Ott a few months after she began treatment, said that from the start, Ott had a “don’t baby me” attitude about her illness.

“She is able to go to a very beautiful and fragile place, but it’s also very honest and it has integrity within it,” Chan said. “And then she flies from there. And that is something I find very beautiful.”

Ott was born in Munich to a Japanese mother, a piano teacher, and a German father, an electrical engineer. She began piano lessons at 4, drawn to the expressive power of music, she said, and when she was 12, she started commuting to Salzburg, Austria, to study with the renowned teacher Karl-Heinz Kämmerling.

After winning a series of prizes, her career took off, and at 19, she signed with the prestigious label Deutsche Grammophon. Still, she began to feel uneasy about classical music’s emphasis on tradition in programming, concert formats and dress. She sometimes faced sexism; a colleague once told her to play a passage of Beethoven like a “cute little Japanese woman,” she said. And her packed touring schedule was taking a toll on her as a musician, she said.

“I felt like people were expecting something from me that I could not provide,” she said. “I was floating around, and I didn’t have stability in the sense of who I was as an artist.”

She began to forge her own path, working with artists like the experimental composer Ólafur Arnalds to record reimagined versions of Chopin. Eager for a more rugged sound, they went searching for out-of-tune pianos in bars in Reykjavik, Iceland.

In 2014, she released “Scandale,” an homage to the Ballets Russes, with the pianist and composer Francesco Tristano, featuring works by Stravinsky, Rimsky-Korsakov, Ravel and Tristano. On tour, they decorated the stage with magenta duct tape and invited the audience to clap along with the music.

“You can really hear the intelligence in the way she performs,” Tristano said. “Nothing is left to randomness or sheer virtuosity. She’s beyond that. She really wants to make a point about the music she’s creating — that it’s relevant today.”

In 2018, on tour in Japan, Ott began to experience health problems, feeling some numbness in her lips and later having difficulty walking.

Her doctors said her symptoms were probably caused by stress. But when she returned home to Munich after another tour a couple months later, half of her body went numb. After undergoing tests, she received her diagnosis: relapsing-remitting multiple sclerosis, the most common form, in which symptoms can flare up and dissipate.

At first, Ott said, she was “scared as hell” and panicked. But she also worried about upsetting her family. “There were lots of times,” she said, “when I just locked myself somewhere and cried.”

Her only knowledge of the illness came from the story of Jacqueline du Pré, the British cellist who died in 1987, at 42, of complications from multiple sclerosis. On the day Ott received her diagnosis, she lost control of her left hand while playing a Chopin nocturne at a recital in Munich. She ran offstage, sat on the floor and cried, and canceled the rest of the concert.

But as Ott read about modern treatments, she grew more optimistic, especially since her illness was in the early stages. In February 2019, about a month after her diagnosis, she posted about it on Instagram.

“An acknowledgment is not a weakness,” she wrote, “but a way to protect and gain strength, both for oneself and for those around us.”

Ott was praised for her courage. When she toured, musicians approached her to share their experiences with multiple sclerosis. But her health challenges also drew scrutiny.

When a critic reviewing one of Ott’s albums last fall suggested that its inclusion of some easier pieces was related to her multiple sclerosis, she shot back. On Instagram, she noted that she had explained her choice of repertoire and that she had plans for more albums. She said that such reductive labeling was “the exact reason why it’s still so hard for many to come out and talk about their own conditions.”

In New York, Ott will perform Ravel’s Piano Concerto in G Major with the conductor Karina Canellakis, who is also making her Philharmonic debut, in a program that includes works by Webern, Strauss and Scriabin. (Last year, the two were featured performing Beethoven in advertisements for Apple Music Classical, the technology giant’s streaming service.)

Canellakis said Ott had a “a serenity about her that is infectious.”

“There’s a sense of pure focus,” she said, “and she inspires everyone else around her to assume that state of being.”

Ott has been refining her interpretation of the Ravel concerto, which she first performed when she was 17, working to mimic the sound of jazz instruments in the piano part.

On a recent evening, she went to the Blue Note jazz club in Manhattan to hear the Japanese composer and pianist Hiromi. The concert felt intimate and laid-back, she said: People cheered freely, laughed, talked and shared food and drinks.

Ott said she strives to create similar connections with audiences.

“Music itself can only fully blossom when we unite in it,” she said. “We have to be vulnerable. That is one of the most beautiful sources of togetherness and strength.”