Rawat, MLA from Rudraprayag constituency, was administered oath as the cabinet minister by Governor Aziz Qureshi at the Raj Bhavan today.
In the House of 70 legislators, 10 ministers were sworn in earlier while one ministerial position was left vacant by the Chief Minister.
After taking the oath, Rawat, told media that "to expedite the development work in the state would be his first priority as the minister."
"I will execute my responsibilities as a minister with complete integrity and will take the development work in the state to new heights through whatever department is assigned to me," he said.
Rawat, who was in the fray for chief ministerial position among others, had earlier said that he would not accept any ministerial position.