Revolution for Prosperity, a party set up only six months ago by businessman Sam Matekane, 64, won 56 out of 120 seats in parliament, according to final results published by the southern African country's electoral commission.
The small kingdom of Lesotho has been governed by a string of coalition governments that have proved fractious and frail for the past decade. No premier has served out a full five-year term.
Matekane, who styles himself as a champion of the country's business community and was considered an outsider in the vote, came close to an outright win but will now have to secure the support of smaller parties to form a government.
Mokhethi Shelile, the spokesperson of the Revolution for Prosperity, says the newly founded party aims to deliver on its promises.
“We are coming in with a message that we need to promote a government that is responsible,” said Shelile.
“We have a very highly successful international business person who is here to actually implement change for the better,” added the RFP spokesperson.
The Democratic Congress party led by Mathibeli Mokhothu came in second, securing 29 lawmakers, according to the Independent Electoral Commission.
The All Basotho Convention party, which led the outgoing government, secured only eight seats, suffering a significant drop in support.
Matekane, believed to be Lesotho's richest man, started off raising donkeys before making a fortune in diamond mining and other business ventures.
Lesotho, which is completely surrounded by South Africa, ranks among the world's poorest countries, with more than 30% of its population living on less than $1.90 a day.
A constitutional monarchy where the king has no formal power, Lesotho has long been beset by political turmoil that has hampered development.