Larsen said that his childhood among the poor was "this mixture of tragedy and baroque, macabre comedy" and gave him an understanding of social problems and the dark sides of society.

Larsen was elected to the city council and served from 1 April 1933 until March 1937 when he chose not to run again.

Following the sudden death of Aarhus mayor, Stecher Christensen, Larsen was chosen as his successor beginning 21 June 1945.

The Danish historian Ole Degn stated that Larsen was a primary influence on social and philanthropic development: new public housing projects, the preservation of natural green spaces and beaches, and the support of the arts, library science and cultural institutions.

Larsen married Ingeborg Carla Held Andersen, the daughter of a postmaster, on 27 November 1919.