Focused on the task at his fingertips and under the soles of his feet before Twin Cities congregations for decades, Gregory Larsen masterfully performed on the church organ, an intricate and imposing instrument with its gleaming metal pipes towering above its multilevel keyboard and countless stop knobs.

But Larsen's passion for the pipe organ also crept deep into its inner workings and made him a leading expert on the grand instrument of spiritual inspiration.

That expertise helped in the construction and installation of pipe organs at Church of the Ascension Episcopal in Denver and at St. Paul's Episcopal Church in south Minneapolis, where his memorial service will take place on Saturday.

Larsen, who served for the last third of the 20th century as choir director and organist in and around Minneapolis and St. Paul, died March 10 in Denver, after a 14-month battle with cancer. He was 64.

"He was just a servant to the instrument," said Patrick Murphy, an organ builder in the Philadelphia area who worked closely with Larsen on the organ for the Denver church. "Many organists don't build, and many builders don't play. He understood the mechanics better than most."

Murphy said that Larsen "helped envision what they were after" in an instrument that costs several hundreds of thousands of dollars. "He was very knowledgeable about organs. ... I could talk very deep, technical jargon with Greg."

It took several years of work, led by Larsen, before St. Paul's new organ took its place in 1998. But for all of the instrument's grandeur and its reverential prominence, Larsen described his church's new organ upon its installation as "a kick to play."

That same organ will let out the music for various hymns at his service Saturday, among them "O God, Our Help in Ages Past" and "There's a Wideness in God's Mercy."

Serving many congregations

Larsen began serving Twin Cities congregations in his early 20s at St. James On the Parkway Episcopal Church in Minneapolis in 1967. He then moved on to St. James Lutheran Church in Minneapolis, St. John the Evangelist Episcopal Church in St. Paul, St. Stephen the Martyr Episcopal Church in Edina and St. Paul's Episcopal Church in Minneapolis.

Larsen was born in Jacksonville, Fla., and grew up Faribault, Minn., where he was a teenage choirmaster and organist at the Episcopal Church's Cathedral of Our Merciful Savior.

After graduating from the University of Minnesota, Larsen studied arts administration at Indiana University.

He taught general and choral music at a number of Twin Cities schools including Minneapolis Northeast Junior High, what is now Shattuck-St. Mary's School in Faribault, the Blake School in Hopkins and Black Hawk Middle School in Eagan.

He also was an instructor, lecturer and adviser to the University of Minnesota, the Minneapolis Institute of Arts, Hamline University and the Canton (Ohio) Museum of Art.

At age 50, he completed a graduate degree from the University of Montana-Missoula in integrated arts education.

He and his wife, Laurie, moved to the Denver area in 2002, where he taught music to middle-schoolers at Graland Country Day School until 2008, then substituted until his cancer diagnosis in January 2011.

Along with his wife, Greg Larsen is survived by sons Peter and Joseph Larsen; and sisters Andrea Strowd and Lisa Larsen. Saturday's memorial service will be held at 10:30 a.m. at St. Paul's Episcopal Church, 1917 Logan Av. S., Minneapolis. A choir will perform with members from several of the churches where he served.

Paul Walsh • 612-673-4482