[4] The bank was founded by Danish trade unions, the Social Democrats and Arbejderkul (union of coal workers) with an initial capital of DKK 2 million, most of which was pledged by Arbejderkul, who were particularly powerful after performing a crucial role in securing Denmark's energy supply during World War I.

During the Great Depression, major shareholder Arbejderkul ran into trouble and the trade union federation joined the ownership of the bank.

In the 1960s the bank went through a major growth period, attracting new private customers and many independent branches were opened throughout Denmark.

On 1 July 2016 AL became the principal sponsor of the football side Brøndby IF in a four-year deal.

AL is also sponsoring Giv Håb, an organisation that supports children who experience serious disease or death in their immediate family.