About six hours before a Chicago Symphony Orchestra concert on Dec. 20, associate concertmaster Stephanie Jeong got a phone call telling her that she would be filling in for concertmaster Robert Chen, who had come down with the flu. That meant she would be front and center that evening, playing his solos in Witold Lutoslawski’s Concerto for Orchestra.

Such last-minute substitutions are rare but they are part of her job, and she didn’t allow herself to get flustered. During the intermission of a matinee holiday concert that same day, she ran through the concerto solos. And instead of the nap she had planned between the two concerts, she just drank lots of coffee and practiced more.

“All went well,” Jeong said. “I have to tendency to work better under pressure. I feel like my brain functions at a faster pace. It’s like survivor skills in a way. Things just kick in and I kind of live off that adrenaline rush.”

Such sangfroid should serve Jeong well when she joins guest pianist Jonathan Biss and assistant principal cellist Kenneth Olsen as soloists in Beethoven’s Triple Concerto in C Major for Piano, Violin and Cello, Op. 56 for CSO subscription concerts March 5-7. The unusual work — the first ever and by far the most famous for such a combination of solo instruments – received its public premiere in 1808.

Jeong’s performances as a soloist will be her first in Orchestra Hall since she made her debut at age 12 with the CSO as winner of its Feinburg Competition. “It will be really fun,” said, who turns 28 in March. “Obviously, I’m friends with my colleague Ken, who will be joining me for it. I’ve never worked with Jonathan Biss before in this type of setting, but I’ve played in the orchestra and accompanied him quite a few times. It’s a really fun piece, and I’m expecting it to be a good time.”

While she has performed solo concertos with such orchestras as London’s Royal Philharmonic and the Jacksonville (Fla.) and Kansas City (Mo.) symphonies, this will be her first time in the Triple Concerto, and indeed, in any concerto with multiple soloists. “I assume it will kind of be like playing with a piano trio — just on a grander scale,” she said. (In the 2015-16 season, she returns centerstage in another solo role, performing three concerts with famed violinist Pinchas Zukerman in J.S. Bach’s Concerto for Two Violins in D Minor, BWV 1043.)

Stephanie Jeong, who won her CSO post as associate concertmaster at age 24, admits, “This is a job that I didn’t plan on having already."

Stephanie Jeong, who won her CSO post as associate concertmaster at the young age of 24, admits, “This is a job that I didn’t plan on having already.” | Todd Rosenberg Photography

As a violin student, Jeong actually dreamed of a solo career, performing recitals and sharing the spotlight with orchestras around the world. But as she got older, she decided that such a path was not for her. “I think more and more I realized that the lifestyle that comes with that is not something that I necessarily wanted,” she said. “I like being home.” So after earning her master’s degree from the Juilliard School in 2010, she opted to seek an orchestral position.

Jeong, a native of East Rutherford, N.J., can never remember a time when she didn’t play the violin. Her parents started her in a Suzuki training program a month before her third birthday, and she has played the instrument since with no hiatus or even an adolescent period of rebellion. “I just always knew it was what I was going to do,” she said. “It was part of my daily life. I had a lot of other hobbies. I took ice-skating lessons, and I was really into art and books, but that was always a constant thing in my life, and I dedicated so much of myself to it every single day from such a young age.”

Shortly after beginning violin lessons, Jeong moved with her family to Chicago. When she was around age 7, her violin teacher suggested she sign up for a master class with Aaron Rosand, a well-known violin virtuoso who has taught at Philadelphia’s famed Curtis Institute of Music since 1981. Afterward, Jeong began traveling every month or two to Connecticut for private lessons with Rosand in his home, and when she was 10, she expanded her studies with him to Curtis, becoming one of the youngest students ever enrolled at the school. Because her father had just begun a shipping company in Chicago and could not move, her attendance at Curtis necessitated a family split, with her mother and little brother living with her in Philadelphia during the school year. “Obviously, that was a huge decision for my family, because I was so young and I obviously wasn’t going to be making that move by myself,” she said.

In all, she studied for 13 years with Rosand, graduating in 2007 from Curtis with a bachelor’s degree when she was 20. She took the following year “off,” but still kept busy substituting in the Philadelphia Orchestra, among other things. In 2007, she also began the first of several summers of studies at the Aspen Music Festival and School, where she met famed violinist Cho-Liang Lin, with whom she went on to study at Juilliard along with Ronald Copes.

After graduating from Juilliard, she began searching for a job. “Luckily,” she said, “there were so many violin openings that year, and a lot of them were in really good orchestras, so I think I had a list of five auditions that I planned on taking.” The first opening on the list was associate concertmaster of the Chicago Symphony. She passed the preliminary round of auditions, but the second round wasn’t until months later. Because she was “quite desperate to get hired somewhere,” she went ahead and auditioned with the second orchestra on her list: the New York Philharmonic. The following week, she was supposed to return for her final round of auditions with the CSO, but they were postponed. So she accepted a violin position with the N.Y. Phil, where she remained for a little less than a year.

Jeong eventually returned to Chicago for finish the auditions for associate concertmaster, and she wound up winning and taking over the post in fall 2011. Moving back to Chicago held appeal not only because of the elevated position but also because it would allow her to live near her parents, who reside in Rolling Meadows.

“To be honest,” she said, “this is a job that I didn’t plan on having already. It’s something that I aspired to have in maybe my mid-30s, but it was an opportunity that became available when I was much younger than I had planned on being. If I waited to that moment to have this job, it would no longer be available for me.”

Before her new post became official, Jeong had to make it through a two-week trial period in April 2011 that happened to coincide with the CSO’s performances of  Verdi’s Otello, not only at Orchestra Hall in Chicago but also on tour at Carnegie Hall. On the podium was Riccardo Muti, generally regarded as the greatest Verdi conductor of his generation. The auspiciousness of the occasion did not escape Jeong. “I just remember it being such an inspiring two weeks for me,” she said. “And I remember thinking that even if I didn’t get hired at the end of the two weeks, that it was just such an amazing experience to be a part of.”

Then, before the CSO left for New York, she learned that she had gained the position. “So obviously that in and of itself was thrilling but to do that program with Muti at Carnegie Hall, knowing that I had the job, it was so amazing — definitely my most memorable concert to date with orchestra.”

For the programs when Chen is scheduled to be off, Jeong takes his place at the head of the violin section and sets the bowings for the works to be performed. The rest of the time, she sits just to Chen’s left and serves as what she calls his “megaphone” to the rest of the violin section, assisting with communication between him and the other players. And, of course, should he become ill or unable to play, she has to be ready to step in on short notice.

Since 2004, when she was a student in Philadelphia, Jeong has played an 1861 violin by Jean-Baptiste Vuillaume (1798-1875), a respected French craftsman who made more than 3,000 instruments. “I’ve been playing on it for more than a decade now, and I love it,” she said. “It’s my baby.”

Since she’s already much further along in her career than she expected to be at this age, Jeong has given little thought to what the next step might be. “It’s going to be really hard for me to leave this job,” she said. “It’s just such a great job. It’s going be really difficult to find a job that is comparable or an upgrade from what I already have going on here.” But she is not closed to future opportunities. “Maybe I will try out for other orchestras in the future,” she said. “You never know. I’m open to it. But right now, I’m very content here.”

Kyle MacMillan, former classical music critic of the Denver Post, is a Chicago-based arts writer.

TOP: Stephanie Jeong, CSO associate concertmaster, arrives in Paris during the CSO’s 2014 European Tour. | Todd Rosenberg Photography