Deshmukh entered active politics and became a member of the Babhalgaon (Latur) Village
Panchayat from 1974 to 1980 and its
Sarpanch (village chief) from 1974 to 1976. He was a member of Osmanabad
Zilla Parishad and Deputy Chairman of Latur Taluka Panchayat Samiti (Latur District Panchayat Committee) from 1974 to 1980. As the President of Osmanabad District Youth Congress from 1975 to 1978, he worked for the implementation of the
Sanjay Gandhi inspired Five Point Programme of the Youth Congress. He organised the youth in Osmanabad district and became the President of District wing of the
Congress (I) party. He was a Member of the
Maharashtra Legislative Assembly from 1980 to 1995 winning the 1980, 1985, and 1990 elections. During this period, he served as the Minister of State and the Cabinet Minister and had the portfolios of the ministries of Home, General Administration, Cooperation, Public Works, Transport, Legislative Affairs, Tourism, Agriculture, Animal Husbandry, Dairy Development Fisheries, Industry, Rural Development, Education, Technical Education, Sports and Youth Welfare. He lost the election in 1995 by a margin of 35,000. He was re-elected to the State Legislature from Latur Constituency in the elections held in September 1999 with a strong comeback winning by a margin of nearly 91,000 in two successive elections, the highest in Maharashtra. He was sworn in as Chief Minister of Maharashtra on 18 October 1999 and served until he stepped down from the post on 17 January 2003, as a result of factionalism in the state unit of the party and succeeded by
Sushilkumar Shinde. He was re-elected to the Legislative Assembly from Latur Constituency in October 2004. He subsequently entered the
Rajya Sabha and was appointed to the Council of Ministers as Union Minister for Heavy Industries and Public Enterprises by
Prime Minister Manmohan Singh on 28 May 2009. He was appointed
Minister of Heavy Industries and Public Enterprises on 19 January 2011 after a cabinet reshuffle. Later on he was appointed Minister of Rural Development. He was appointed
Minister of Science and Technology and
Minister of Earth Sciences on 12 July 2011. ==Scams and controversies==