Pita Limjaroenrat failed on Thursday in his first bid to become the country’s next prime minister.
He was unable to secure the required endorsement of more than half of the members of parliament.
The final tally was 324 votes in favour, 182 against and 199 abstentions, among the 705 members participating. The Move Forward Party (MFP) leader needed 375 votes — a simple majority of the 749 combined House and Senate seats — to win the office.
Mr Pita received 311 votes in favour from MPs and 148 against, with 39 abstentions. He received just 13 votes in favour from senators, 34 against and 159 abstentions.
Second and third rounds of voting would take place on July 19 and 20. It is not yet clear whether the name of the Move Forward leader will be put forward again on one or both occasions.
“We accept the result, but we are not retreating,” Mr Pita told reporters shortly after the results were announced. “The result was not what we expected. We will work hard to gather support for the next vote. I will strategise again to make sure next time we get the votes needed.
“We will not change our policies, we must keep our promise to the people,” he added.