He was born in Kristiania[1] as a son of Gustaf Aspelin (1857–1917)[2] and Elisa Holmboe (1865–1926).
[4] His sister Karen married Ragnar Sommar Bruzelius, mayor of Gustaf's city of origin Kristianstad.
[5] Jonas Aspelin attended commerce school, and spent about five years abroad in Germany, England and the United States.
Gustaf Aspelin died in 1917, and Jonas took over, and later took his brother Knut on board as co-owner.
[2] He was also a deputy chair of the employers' association Jerngrossistenes Forening and supervisory council member of Storebrand.