COPENHAGEN - Christiansen replaces Bali Padda, who took over as interim CEO in January. Padda will hold a "special advisory" role within the group.
Chairman Joergen Vig Knudstorp said Thursday that said Christiansen, 51, will start Oct. 1.
Lego said Christiansen became chief executive of Danish audio solutions maker GN Netcom at the age of 33, and joined the family-owned Danfoss in 2004. He became its head four years later, a job he held until June.
"He transformed a traditional industrial company into a technology leader," said Vig Knudstorp — a former Lego CEO himself — adding he was confident the toymaker "will continue to flourish" under Christiansen.
In March, Lego said its 2016 revenue grew 6% to 37.9bn kroner ($6 billion), the highest figure in the company's 85-year history. The privately held group's net profit rose to 9.4 billion kroner ($1.5bn).
Padda, a 61-year-old India-born Brit and Lego's former chief operations officer, was only considered a temporary CEO. In a statement, Vig Knudstorp said the transition to find a new CEO "occurred more rapidly" than anticipated.
Padda, who joined Lego in 2002 in Enfield, Connecticut, was praised by Vig Knudstorp, who said Padda "played an integral role in the turnaround of the Lego Group and during his time as CEO created a solid foundation from which to continue to transform the company."