Salazar was born into an established ranching family, and he spent his childhood in the mountainous pasturelands of southern Colorado. He earned a bachelor's degree in political science from Colorado College in 1977 and a law degree from the University of Michigan in 1981. After graduating, he returned to Colorado to practice law, specializing in environmental issues and water rights.

Salazar, a Democrat (Democratic Party), entered the political sphere in 1986, when he was named chief legal counsel for the governor of Colorado. He remained in that role until 1990, when he took over as executive director of the state's department of natural resources. While there Salazar gained a reputation as a moderate who viewed land stewardship as a compromise between business interests and environmental concerns. He became the first Hispanic to be elected to state office in Colorado, in 1998, when he successfully campaigned for the position of attorney general. He won reelection four years later but interrupted his second term with a run for the U.S. Senate in 2004. Salazar's victory, in what had been regarded as a solidly Republican state, was seen as a possible sign of a political shift in the mountainous west. Nominated by Obama to serve as secretary of the interior, Salazar resigned his Senate seat on Jan. 19, 2009 (the day before Obama's inauguration), and was confirmed by the Senate in a unanimous voice vote the following day.