Kenneth Jennings is credited with using his humble manner and consummate musicianship to elevate an already world-class St. Olaf Choir.

Jennings, 90, died Aug. 20 at his home in Northfield.

He was conductor of the St. Olaf Choir from 1968 to 1990, taking over after 56 years of leadership from founder F. Melius Christiansen and then his son, Olaf.

Jennings is noted for increasing the global reach of the ensemble — and its performance scope.

Jennings, a 1950 graduate of St. Olaf College and a student of Olaf Christiansen, earned a master’s degree in music from the Oberlin Conservatory and a doctor of musical arts degree from the University of Illinois at Urbana-Champaign. In 1953, he returned to St. Olaf and joined the music faculty.

Jennings was on the music faculty for 15 years and served as Olaf Christiansen’s assistant conductor, but was still surprised to be chosen as the choir’s third conductor.

“Olaf got to the point that he thought that he would be ready to retire, and he just called me into the office and said, ‘We’d like you to become the new conductor of the St. Olaf Choir,’ ” Jennings recalled in “A Century of Singing,” St. Olaf’s history of the choir.

Jennings noted that the offer was “a bit of a shock.” When he said he needed time to contemplate the offer, Olaf Christiansen said that was fine — so long as the answer was ready for a meeting with the school’s president the next day.

The St. Olaf Choir earned its fame with national and international tours under the Christiansens.

Jennings expanded the choir’s global footprint with a tour of Asia in 1986. In 1988, it was one of only five choirs in the world invited to participate in the Olympic Arts Festival in Seoul.

Jennings also was credited with bringing more contemporary music to the choir.

“I thought that the repertoire had been a little bit narrow, and there was a lot more music — interesting music — around, and I looked for it,” Jennings said in a “A Century of Singing.”

Jennings also added instrumentation to the choir. In 1969, he added a flute and guitar as accompaniment. Later, full orchestral accompaniment would be added.

Anton Armstrong was a student of Jennings and later succeeded him as choral director in 1990.

“There was a humbleness in Kenneth Jennings and in his music-making. He was never the one who was most important on the stage,” Armstrong said. “He was part of truly being a shepherd in many ways to all of us.”

Jennings was soft-spoken but demanding, he said.

A consummate musician, he communicated beautifully through his hands.

“He did with voices what a visual artist does with clay,” Armstrong said. “He molded the sound with his hands — literally.”

Joe Shaw, professor emeritus of religion at St. Olaf, was a colleague of Jennings and author of the “The St. Olaf Choir: A Narrative,” published in 1997.

“He inherited a treasured musical tradition from the Christiansens, respected it and let it sing, and added his own musical artistry to the growth and enrichment of the St. Olaf Choir,” Shaw wrote.

“His legacy was to take the enormously important and valuable choral heritage that came down from the Christiansens and to keep it going, but also to revitalize it and refresh it,” Shaw said. “Kenneth was well known for the fact that he took some chances, and that is part of what was admirable about him.”

Jennings is survived by his wife, Carolyn, professor emeritus of music at St. Olaf; and his three children. Funeral services will be held at 2 p.m. Sept. 18 at St. John’s Lutheran Church in Northfield.