The junta-linked Palang Pracharat party now has 115 seats in the lower house, only 11 votes shy of a majority in the combined parliament thanks to 250 military-appointed senators.
The results were announced more than a month after the March 24 vote, the first election since the military seized power in a 2014 coup.
It was held under new rules crafted by the generals, including the creation of appointed senators who can vote for prime minister.
Palang Pracharat party leader Uttama Savanayana said on Facebook after the results that it is "ready to work and move forward with our policies we promised to the people."
Despite the booked-in advantage, the lower house results leave the party needing a little help from coalition partners.
The most obvious candidates are Bhumjaitai and the Democrat Party, which both have more than 50 lower house seats.
Officials from both said Wednesday they have yet to reach a decision.
"The party is split," longtime Democrat official Sirichok Sopha told Agence France-Presse.
The election was widely seen as a choice between junta-backed rule and those aligned with billionaire ex-premier Thaksin Shinawatra.
A whopping 27 parties will have seats when parliament convenes within 15 days.
Wednesday's results are likely to set off horse trading, negotiations and challenges.
'Abuse of the law'
The Shinawatra-linked Pheu Thai party won the most lower house seats with 136 – posing a legitimacy crisis for the gruff junta leader Prayut should he become prime minister.
Pheu Thai threatened to take legal action over the formula used to calculate seats, calling the Election Commission's action "an intentional abuse of the law and against the constitution."
It is part of a lower house coalition with 6 other parties, including upstart newcomer Future Forward headed by telegenic billionaire Thanathorn Juangroongruangkit, who led the youth-oriented force to third place in the popular vote and 80 seats.
But Thanathorn has been hounded by legal complaints that the rising star has blasted as "political sabotage."
He said Wednesday in a press conference that Future Forward was ready to talk to any party "that does not support Prayut as a prime minister in order for our democracy to move forward."
The Election Commission has come under fire for wildly inaccurate initial counts, 2.1 million invalidated ballots, and the staggered released of full results.
It has been flooded with complaints since the election, and recounts and new voting sessions were held in a handful of polling stations.
Even if Prayut clinches the prime minister's post, Palang Pracharat may not cobble together enough lower house seats to ram through legislation.
"That means a stalemate in terms of making any policy," said political scientist Napisa Waitoolkiat of Naresuen University.
The junta has portrayed itself as a necessary force to maintain stability in Thailand, which is broadly divided between populist forces and an arch-royalist army-backed elite.
The release of election results comes two days after the end of the elaborate coronation for Thai King Maha Vajiralongkorn, the 10th monarch of the Chakri dynasty. – Rappler.com