For pastors, the Rev. Duane Addison was an intimidating presence in the pews of St. Anthony's Nativity Lutheran Church when he joined 25 years ago — an erudite theologian with a national reputation for social justice advocacy.

But, says Nativity senior pastor Glenn Seefeldt, Addison's ritual of warmly thanking him after each service quickly dispelled that self-consciousness.

Addison, a longtime professor of religion, died in the Twin Cities last month from complications from Parkinson's disease. He was 88. During a distinguished career as a pastor and educator, he worked to elevate the voices of marginalized communities, especially American Indian tribes in South Dakota and Minnesota. After four degrees and extensive scholarship, Addison maintained a curiosity about other spiritual traditions — and a knack for setting others at ease.

"Duane was one of those brilliant theologians who never condoned arrogance or haughtiness," Seefeldt said. "People always left their encounters with Duane with their heads held a little higher and their shoulders a little more squared."

A native of Tracy, Minn., Addison was class valedictorian at Marshall High School and went on to graduate magna cum laude from the University of Minnesota. There, he experienced a crisis of faith that eventually brought a deepening of belief and a conviction that he was called to serve in the church.

After serving in the Navy Supply Corps for three years, he earned a master of divinity degree from St. Paul's Luther Seminary in the same year he married his first wife, Carol, with whom he would have three children. Later, he obtained a master's and a doctorate at Yale University and was ordained as a Lutheran pastor.

As a campus minister at the University of Iowa, Addison exposed students to key influences in Christian theology, including Dietrich Bonhoeffer, the renowned theologian executed by the Nazis, says Lynne Lorenzen, an Augsburg professor emerita who was a student there at the time.

Addison went on to teach at what is now Augustana University in Sioux Falls for 25 years. Not long after he arrived on campus, a group of American Indian students told him that they did not see their community reflected anywhere in the curriculum, says Addison's stepson the Rev. Paul Erickson, bishop of the Greater Milwaukee Synod of the Evangelical Lutheran Church in America. Addison joined them in a push to change that.

"He had deep-seated respect for another's way of looking at the world and at God," Erickson said.

Over time, Addison cultivated deep ties with the Lakota community. He advocated with the Congressional American Indian Policy Review Commission. He spoke openly about the Christian church's troubling role in assimilation efforts and the need to make amends, starting with bearing "humble witness." Addison's daughter, Linnea Fonnest, recalls the respect with which he was greeted when the family attended celebrations on the Rosebud and Pine Ridge reservations.

Indeed, said Minneapolis ELCA Bishop Ann Svennungsen in her eulogy, Addison had a long track record of engaging with social justice issues: poverty, gay rights, peace in the Middle East and more. He was a key player on the ELCA Commission for Multicultural Ministries and helped found the now-defunct South Dakota Peace & Justice Center, which over the years focused on poverty and criminal justice reform.

"He was always studying and learning and growing for the sake of the church and the world," she said.

After retiring from Augustana, Addison moved to the Twin Cities in 1993 with his second wife, Eva. He taught at Augsburg and, for more than 20 years, led a weekly 6:30 a.m. study breakfast at Nativity Lutheran. Even as Parkinson's started taking a toll, Seefeldt said, Addison continued reading voraciously, keeping up his famed system of highlighting, underlining and scribbling notes in the margins.

Addison also is survived by his brother, Curtis; his sons Richard and Roy; his stepsons Stephen and Andy; one grandchild and four stepgrandchildren. Services have been held.