Waldemar Ager was born in Frederikstad, Norway, March 23, 1869. Ager's father immigrated alone to America, living in Chicago. Ager went to join his father in Chicago in 1885 when he was 16 years old. Soon after his arrival, Ager worked at Norden, Chicago's largest-circulation Norwegian language newspaper. Ager became one of the leaders of the Prohibition movement and helped form hundreds of total abstinence societies and Good Templar lodges across the Upper Midwest. He became involved with a Norwegian temperance lodge in Chicago in the late 1880s. The lodge had a small-circulation monthly newspaper, and Ager began writing articles for it. Ager would remain an avholdsmann (a teetotaler) his entire life, before, during, and after the decade-long period of Prohibition in the United States.

At age 23 he moved to Eau Claire, WI, after being offered a job at a Norwegian temperance newspaper called Reform. The editor of Reform died in 1903, and Ager took over the position. Eventually Ager would come to own the paper. Reform folded shortly after Ager's death in 1941. Ager wrote six novels and other short stories. He was never commerically successful like his friend Ole Edvart Rølvaag. He was a humorist who specialized in character sketches and dramatizing the tragic-comedy of the lives of Norwegian immigrants. Some of his more important works, translated into English, are Christ before Pilate, On the Way to the Melting Pot, Sons of the Old Country, and I Sit Alone. Ager was a popular speaker, traveling the circuit to speak wherever Norwegian-Americans gathered. In 1916 on Syttende Mai, Ager shared a platform with William Jennings Bryan. Ager married a Norwegian immigrant from Tromsø, Norway, named Gurolle Blestren, with whom he had 9 children. He died in Eau Claire, WI, August 1, 1941 at age 72.