He pursued undergraduate study in mathematics, statistics and economics at Stockholm University.
Mäler specialized in economics at the graduate level, attending the Massachusetts Institute of Technology and Stanford University in the United States before earning a doctorate from Stockholm University in 1972.
Mäler was elected to the Royal Swedish Academy of Sciences in 1981, and served on its Committee for the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel until 1994.
Mäler and Partha Dasgupta founded the Beijer Institute of Ecological Economics in 1992, and Mäler served as the institute's director through 2006.
He and Dasgupta shared the Volvo Environment Prize in 2002.