Scolari left his job as technical director at Athletico Paranaense to sign on at the Belo Horizonte-based club, where he succeeds Argentine coach Eduardo Coudet (48).
Scolari took Athletico to the Copa Libertadores final last year during a six-month spell in charge and announced his retirement in November, continuing at the club as a technical director.
In a colourful career spanning more than 40 years, Scolari has enjoyed success at both club and international level but will be most remembered for his highs and lows with his native Brazil.
Scolari famously led Brazil to their 2002 World Cup triumph in Japan but was also the man in charge when they suffered their most embarrassing defeat, a 7-1 drubbing by Germany at home in the 2014 World Cup semi-final.
He took Portugal to the final of the 2004 European Champion and semi-finals of the World Cup in 2006 before taking charge at Chelsea, where he endured a turbulent seven-month spell before being sacked.
At club level, Scolari has enjoyed success in Brazil and China. He won the Brazilian Serie A and Copa Libertadores with both Gremio and Palmeiras, and the Chinese Super League and Asian Champions League at Guangzhou Evergrande.
Scolari's first game in charge of Atletico will be away to Fluminense on June 21. Atletico are fourth in the league with 18 points from 10 games.
