His name was proposed by BJP leaders Prakash Pant and seconded by Satpal Maharaj. The two men were also in the race for the post.
All the other 54 Bharatiya Janata Party legislators then unanimously approved Rawat's candidature.
A former associate of now Prime Minister Narendra Modi, Rawat was the Agriculture Minister in the previous BJP government in Uttarakhand, which was carved out of Uttar Pradesh in 2000.
Rawat will be sworn in as the ninth Chief Minister of the hill state on Saturday at a grand ceremony at the Parade Grounds in the presence of Modi and BJP President Amit Shah.
Party sources told IANS that six ministers were also likely to be sworn in with Rawat.
"Rawat was elected leader of the BJP Legislature Party... The proposal was accepted unanimously," Union Minister Narendra Singh Tomar told the media here.
Tomar said Rawat later met Governor Krishan Kant Paul and staked claim to form the new government.
Rawat was elected in the presence of party observers and senior leaders from Delhi -- Tomar, Saroj Pandey, Dharmendra Pradhan, Shyam Jaju and J.P. Nadda -- as well as Uttarakhand BJP President Ajay Bhatt.
Elected from Doiwala, Rawat is widely regarded in the party for his organizational skills. He is a 'Pracharak' in the Rashtriya Swayamsevak Sangh (RSS), the BJP's ideological parent.
Besides being closely associated with Modi when the present Prime Minister was a BJP General Secretary, Tomar also worked with Amit Shah in Uttar Pradesh during the 2014 Lok Sabha polls.
That was when the BJP created history by sweeping 73 of the 80 Lok Sabha seats in Uttar Pradesh, leaving only five to the opposition and two to an ally.
Rawat was also credited with the BJP win in Jharkhand.
In the just ended assembly elections, the BJP again stunned the Congress by winning 57 of the 70 seats in Uttarakhand.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)