Last summer he was elected as chair of the Swedish People's Party, the smallest of the three government partners. However the handover of the portfolio was delayed until now because of the Finnish EU Presidency term.
On New Year's Day, Wallin formally succeeds Jan-Erik Enestam, who was the longest-serving minister in the current cabinet. He too had been leader of the Swedish People's Party.
Wallin, a 39-year-old from Vaasa, is a former newspaper editor with a degree in political science. He formerly served as State Secretary of the Environment Ministry under Enestam.
In a press conference on Friday, Wallin backed the incineration of waste to produce energy. However he stressed that reduction of waste should be the primary goal. YLE