| 1869 | Born March 23, Fredrikstad, Norway, to Martinius Mathisen Ager of Eidsberg and Fredrikke Marie Johnsdatter Stillaugsen, known as Mathea, of Fredrikstad. |
| 1871 | Family moves to Græsvig (now Gressvik), across the Glommen (now Glåma) river from Fredrikstad. |
| 1873 | Enters school at age four and a half. |
| 1882 | Family having moved to Christiania (Oslo), Waldemar leaves school at age thirteen to find employment. |
| 1883 | Father Martinius emigrates to America to settle in Chicago as a custom tailor. |
| 1885 | Mother Mathea and three children emigrate to Chicago; Waldemar begins as apprentice printer at Norden, a Norwegian-American weekly newspaper. |
| 1887 | Joins the Harmony Total Abstinence Society, becomes its secretary. |
| 1891 | Becomes editor of Templarbladet, a four-page temperance monthly published in Milwaukee, Wisconsin. Becomes a naturalized citizen of the United States. |
| 1892 | Moves to Eau Claire, Wisconsin, to work as a printer in the office of Reform, a weekly Norwegian newspaper advocating temperance and prohibition. |
| 1894 | Paa drikkeondets konto: Fortallinger og vers published in Eau Claire at Reform's printshop. Father Martinius dies in Chicago and is buried in Mt. Olive Cemetery. Mother moves to Eau Claire. |
| 1896 | Promoted to business manager and co-editor of Reform. |
| 1899 | Marries Gurolle Blestren from Tromsø; wedding trip to New Orleans. I strømmen, en fortælling published in Eau Claire. |
| 1900 | First visit to Norway since emigration. |
| 1901 | Afholdssmuler fra boghylden published in Eau Claire. |
| 1903 | Becomes editor of Reform. |
| 1905 | Starts and edits Kvartalskrift, journal of Det Norske Selskab i Amerika. |
| 1906 | Fortællinger for Eyvind published in Eau Claire. |
| 1907 | When You are Tired of Playing: Stories for Eyvind translated by J. J. Skørdalsvold and published in Eau Claire. |
| 1908 | Becomes a member of the Eau Claire Public Library Board. Hverdagsfolk, short stories, published in Eau Claire. |
| 1910 | Kristus for Pilatus. En norsk-amerikansk fortælling published in Eau Claire. |
| 1911 | Presten Conrad Walther Welde, Norwegian title of Kristus for Pilatus, published in Christiania by Aschehoug publishers. |
| 1912 | First Eau Claire citizen to appear in Who's Who in America. |
| 1913 | Mother Mathea dies in Chicago and is buried in Mt. Olive Cemetery. |
| 1914 | Second visit to Norway: director of Wisconsin exhibit at Constitution Centennial, Christiania. Edits Afholdsfolkets festskrift, published in Eau Claire. |
| 1915 | Edits Norge i Amerika, a reader, with G. Bothne, published in Christiania by Dybwad publishers. |
| 1916 | Fortællinger og skisser published in Eau Claire. Oberst Heg og hans gutter published in Eau Claire. |
| 1917 | Paa veien til smeltepotten, a novel, published in Eau Claire. |
| 1918 | Udvalgte fortællinger published in Minneapolis by Holter publishers. |
| 1919 | Fiftieth birthday, honored by friends with a gift of a thousand dollars; buys cottage on Lake Chetek. |
| 1921 | Ny samling. Fortællinger og skisser published in Eau Claire. |
| 1923 | Awarded Order of St. Olaf by King Haakon of Norway. Det vældige navn. Et drømmebillede fra verdenskrigen published in Eau Claire. |
| 1924 | Christ before Pilate: An American Story published in Minneapolis by Augsburg Publishing House. |
| 1926 | Gamlelandets sønner, a novel, published in Oslo by Aschehoug publishers. |
| 1929 | Receives honorary Doctor of Letters (Litt. D.) from St. Olaf College, Northfield, Minnesota. Hundeøine, a novel, published in Oslo by Aschehoug publishers. |
| 1930 | Underforvandlingens tegn. Fortallinger og saadant published in Eau Claire. |
| 1931 | I Sit Alone, translation of Hundeøine by Charles Wharton Stork, published in New York by Harper's. |
| 1934 | Third and last visit to Norway, lecture tour sponsored by Nordmanns Forbundet, with daughter Valborg. |
| 1938 | Skyldfolk og andre, short stories, published in Eau Claire. |
| 1939 | Receives St. Olaf medal from King Haakon. |
| 1941 | Dies August 1, and is buried in Lakeview Cemetery, Eau Claire. |