He was born in Grue as the son of bailiff Christoffer Larsen and his wife Olea Bredesen Ramsøyen, and was named after his maternal grandfather.
In June the same year he married Henriette Caroline Sætre; the marriage lasted until her death in 1881.
[1] Oversigt over de norske bygdemål, an overview of Norwegian rural dialects, followed in 1897,[2] when Larsen had managed to visit most of Norway.
[1] In 1899 he applied for a vacant professorship at the University of Kristiania, but Marius Hægstad was appointed.
From 1902 he was engaged with describing Norwegian city dialects, a task on which he would spend most of his remaining life.