According to a press release, Kê‰ge told the company's board that he wanted to "pursue other opportunities."
"We deeply appreciate the artistic excellence and leadership Jonas Kê‰ge has provided Ballet West during his tenure, and we are sad to see him depart," said board chair Carol Carter. "He has choreographed and successfully presented many exciting productions, most notably the 2006 performances of Romeo and Juliet and Swan Lake."
Kê‰ge's tenure included performances at the 2002 Winter Olympic Games, a tour of China, and a trip to the Edinburgh Festival.
In early 2005, facing a budget deficit, Ballet West scaled back its season and reduced the number of dancers in the company. In response, dancers formed a union and joined the national American Guild of Musical Artists. After a period of tension, the two sides signed a contract in November.
Ballet West will form a search committee of board members and "experts" to seek a new artistic director, Carter said. An advisory panel of staff and dancers and a group of trustees and donors will assist the committee.
A native of Stockholm, Kê‰ge studied at the Royal Swedish Ballet's school and joined the company at the age of 17. He later danced with American Ballet Theatre, where he became a principal dancer, and Stuttgart Ballet, Geneva Ballet, and Zurich Ballet. In 1988, he was named artistic director of Sweden's Malm‹ Opera Ballet.
In addition to his own stagings, Kê‰ge has added works by George Balanchine, Antony Tudor, John Cranko, and William Forsythe, among other choreographers, to the repertoire of Ballet West.