Christiansen transformed his small woodworking shop, which initially sold household products, into a manufacturer of wooden toys.

Christiansen was born on 7 April 1891 in Omvraa Mark, Filskov, South Jutland, Denmark, which is 20 km northwest of Billund.

[2] It was while he was working as a farmhand from the age of six that Christiansen developed a fascination with whittling wood, in between the two days per week that he attended school.

[2] During the late 1920s, the business focused on restoring and developing new buildings and also producing household goods for the local community.

[4] Following this event, Christiansen decided to expand his business and employed an architect to build a larger workshop and family home.

With the business slipping into bankruptcy, he refused to stop producing toys when his siblings requested this as part of a bailout loan.

[10][11] Christiansen's company moved primarily to the production of wooden toys, such as yo-yos, pull-along animals and trucks.

[citation needed] Years later, he said, "Not until the day when I said to myself, 'You must make a choice between carpentry and toys' did I find the real answer.

[5] Christiansen maintained his business through the Great Depression and Nazi Germany's occupation of Denmark in World War II.

A short circuit created an electrical fire, which resulted in the loss of his factory and his entire stock and blueprints.

[9] In 1947, the Lego company was the first toy manufacturer in Denmark to purchase a plastic injection moulding machine, which was so expensive that it cost more than twice the previous year's profits.

[14][15] Ole died just before his son used the Automatic Binding Brick as the basis for the company's "System of Play", which was the foundation of the modern Lego building toy.