Oscar Larson was born November 1, 1877, to Victor and Caroline Tapper Larson in Galesburg. His parents had been married in Sweden in 1869 and emigrated to Galesburg in May, 1871. The following year they united with the First Lutheran Church and remained members the rest of their lives. They had two daughters and three sons.

Victor Larson was a pattern maker. He worked for the Brown Cornplanter Works, Frost Manufacturing Company and the Chicago, Burlington and Quincy Railroad coach department. He also established his own contracting company. He died October 19, 1927, and Mrs. Larson died July 23,, 1934. They were buried in Linwood Cemetery.

Oscar was about two months older than Carl Sandburg and lived a short distance from the Sandburg home on Berrien Street. The boys walked to school together. They called one another by their nicknames “Husky” and “Cully.” They walked the dusty road to Knoxville to attend the Knox County Fair. They swam together in the old brickyard pond on that hot Sunday afternoon, rode in the paddy wagon to the city jail and appeared before Justice B.F. Holcomb the next morning.

In 1902, Oscar became a charter member of the lather's union and served as the treasurer for a number of years. He worked for the C.B.&Q. as a pipefitter during World War I. In 1927 he became manager of the Chicago Motor Club office in Galesburg and also served on the County Board of Supervisors. In 1931, Mayor Joe E. Anderson appointed Larson superintendent of the city streets. He was appointed zoning commissioner in 1941. He served as a Republican precinct committeeman for twenty-five years in the Fourth Ward. He was a member of the East Main Congregational Church. Larson was also active in the Modern Woodmen of America for many years

Oscar married Nellie V. Russell of Oneida on June 15, 1904. They had one daughter and three sons.

In the fall of 1951, Carl Sandburg returned to Galesburg seeking information for his autobiography, Always the Young Strangers. The poet had no public engagements. He spent most of his time with Husky Larson. They visited in the commissioner's office at City Hall.

It happened to be Larson's seventy-fourth birthday so Sandburg was invited to the Larson home for dinner in the evening. Mrs. Larson was in Ohio visiting their daughter, so Oscar's sister-in-law, Mrs. Ernest Larson, prepared a traditional Swedish dinner, including lutefisk.The two men spent the time looking at old photographs and recalling their boyhood days, especially the skinny dip on East Fifth Street more than sixty years before.

Oscar Larson had a stroke which affected his ability to speak. He was mute for the last eighteen years of his life. When the Memorial Service for Carl Sandburg was held on September 1, 1967, at the Sandburg Historic Site, Jack Larson took his father to the ceremony.

Oscar Larson died February 2, 1971, at the age of ninety-three. He was the last surviving member of the Dirty Dozen, the group of boys who grew up together and had their group photograph taken on a Sunday afternoon in the 1890s.