Clarence was born October 26, 1908 in Star Township, Red Lake County, MN and was baptized Ole Clarence Johnson. His father died shortly before his birth and following the marriage of his mother, Gurty Vatne Johnson, to Ole Nelson, he became known as Clarence Nelson.

When he was eight years old, his mother and younger sister died in a house fire and Clarence was asked to choose if he wanted to live with his paternal grandmother or stepfather and younger brothers. He opted to remain a member of the Nelson household and attended school at District 38 school in Highlanding Township.

As a young man, Clarence traveled throughout the country and held a variety of jobs. On February 22, 1934, he married Myrtle Heden and the couple made their home in the Highlanding area. They were the parents of four children, Kenneth, Vernon, Genevieve and Doris. The family later moved to Thief River Falls, MN.

Clarence continued to enjoy a variety of occupations, including the operation of heavy construction equipment and helping build the Alaska Highway. During World War II, he worked on submarines and destroyers for the Civil Department in Vallejo, CA. He returned to northern Minnesota and later moved to Minneapolis where he worked as a crane operator.

From 1958 to 1974, Clarence was employed as a diesel mechanic for Suburban Transport, maintaining a fleet of tanker trucks. In 1971, he was united in marriage to Mae Helgerson at Reno, NV. The couple made their home in Champlin, MN and Clarence continued to work following his retirement from Suburban Transport. In 1990, Clarence and Mae moved to Thief River Falls where they built a home.

Licensed since 1940, Clarence was an avid amateur radio operator and enjoyed talking to people all over the world. He also enjoyed traveling and was a loyal Minnesota Twins fan.

He was a member of St. John Lutheran Church.

Survivors include two sons, Kenneth (Geraldine), Oklee, MN and Vernon (Elaine), Thief River Falls, MN; daughter, Jennie (Allan) Swenson, Hettinger, ND; son-in-law, Phil Ostby, Lindstrom, MN; 10 grandchildren; 21 great-grandchildren; 4 great great-grandchildren and numerous nieces and nephews.

Preceded in death by wife, Mae; daughter, Doris Ostby; grandson, Terry Nelson; parents; brothers, Arthur and Norman Nelson and sister Anna Nelson.