When Ruth Ann Koesun emerged from her Lake Shore Drive apartment to head to work as an assistant at Chamber Opera Chicago, people saw a woman whose carriage and poise were as impeccable as her size 2 Chanel suits.

That’s because she had danced all over the world with the powerhouse American Ballet Theatre, including a triumphant tour that gave a lift to London audiences who’d been worn down by war.

On July 4, 1946, the troupe became the first American ballet company to appear in London after World War II and the first to appear at the Royal Opera House in Covent Garden. On opening night, Ballet Theatre received 12 rapturous curtain calls.

Ms. Koesun, who grew up in Chicago’s Chinatown, became the toast of London for her performance in “Fancy Free,” a ballet about American sailors living it up on leave.

She has died of natural causes at her Lake Shore Drive apartment at 89, according to her goddaughter Ellen Coghlan.

Ruth Ann Koesun, who danced with the American Ballet Theatre. | National Ballet of Illinois

“She was beautiful,” Coghlan said. “She was very classic.” 

When she danced, “It was magnificent,” said Mary Jane Fudacz, a friend. “She just kind of floated. . .she never exceeded 93 pounds in her life.”

Ms. Koesun performed on bills with some of the world’s finest classically trained dancers, among them Alicia Alonso, Erik Bruhn, Nora Kaye, Maria Tallchief and Violette Verdy.

Ballerinas Ruth Ann Koesun (seen in profile) and Melissa Hayden on the cover of Life in November 1947.

She also appeared on a 1947 cover of Life magazine and danced in “Billy the Kid” at the White House in 1962 for President John F. Kennedy and First Lady Jacqueline Kennedy.

She had scintillating memories of her tours, including the time actor Yul Brynner spilled champagne down ballerina Norma Vance’s dress at a party in San Francisco, where he was performing in “Lute Song.”

After retiring from ABT in 1969, she was a co-director of the dance department at Hull House Association, toured as a ballerina with the First Chamber Dance Company of New York and was executive director of the Association for Illinois Dance Companies.

“Ruth Ann Koesun pioneered with ABT in its early touring days, traveling everywhere with the company to cities and towns across the globe,” said Kevin McKenzie, the company’s artistic director. “As an early member of Ballet Theatre, she set an example of dignity and perseverance for many generations of ABT artists.”

Ruth Ann Koesun. | Newberry Library

Young Ruth Ann grew up in the 2300 block of Wentworth Avenue, the daughter of Dr. Paul Z. Koesun, a Chinese-American physician, and Mary Mondulick, who was of Russian descent.

“She was very proud of her Asian background,” her goddaughter said.

At 6, she started training with instructor Edna Lucille Baum. Ms. Koesun also studied with the Stone-Camryn School of Chicago, which funneled many talented performers to ABT. And she danced with the Swoboda School corps de ballet. She graduated from Mercy High School.

When she began dancing in the 1940s and 1950s, critics and arts editors often mentioned her ethnicity as something exotic, calling her “a young Chinese-American girl” or “the 19-year-old Chinese-American baby ballerina.” A 1947 article in the Minneapolis Star said her performance meant “The Oriental influence will be in the ballet at Lyceum theater next week.”

Ms. Koesun’s roles included performing in Agnes de Mille’s “Fall River Legend,” “Les Sylphides,” “Graduation Ball,” “La Fille Mal Gardee,” the title role in “Giselle” and the Sugar Plum Fairy in “The Nutcracker.”

“She was lyrical,” said Richard Covello, a writer and performing arts critic. “You could call her neo-Romantic.”

Ruth Ann Koesun (onstage on left, in lace mantilla and dark choker, toe pointed) with President John F. Kennedy and Jacqueline Kennedy for a 1962 White House performance of the ballet “Billy the Kid.” Composer Aaron Copland is in tails, back to camera, on right.

After retiring from dance, she worked as an archivist at the Newberry Library and at a Chanel boutique and the Happy Hanger upscale resale store at 3559 N. Broadway.

Ms. Koesun loved Chanel No. 5, grew up with boxer dogs and also loved felines. She had a cat named Isis for 20 years. Last October, she took in a new cat, Nefertiti, a rescue from Hurricane Harvey who’s now being cared for by a friend.

A marriage to fellow ABT principal Eric Braun ended in divorce. Her frequent dance partner and fiance, former ABT principal John Kriza, died in 1975. The Berwyn native drowned in the Gulf of Mexico while on vacation.

In her wallet, she kept a photo of Odette, a favorite dog, with an inscription Kriza wrote on the back: “From Johnny, With all my love.”

Visitation will be from 9 a.m. Saturday until a 10:30 a.m. funeral Mass at Holy Name Cathedral.

Ruth Ann Koesun in 1949. | File photo