He was elected by the party councillors in JMC headquarters here.
Lahoti secured 69 votes out of total 91 wards.
His nearest rival and independent candidate Sushil Sharma could only get 21 votes.
One vote was rejected out of the total 91.
"Out of 91 councillors, 69 voted in favour of Ashok Lahoti after which he was declared elected," Jaipur Collector Siddharth Mahajan told PTI.
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Lahoti was appointed as state BJP spokesperson during the recent change in party's executive body.
He said he would work to make Jaipur a clean and smart city as per the vision of Chief Minister Vasundhara Raje.
A former Yuva Morcha president, Lahoti was said to be the first choice of Parnami for the post.
A builder by profession, Lahoti had earlier failed to get support of RSS and city MLAs.
He was also considered a strong candidate for the party to represent Civil Lines assembly seat in 2013 but lost the race to Arun Chaturvedi, now a cabinet minister.
His predecessor Nirmal Nahata had resigned from the post on Tuesday citing personal reasons.