By Agence France-Presse
Republicans held their majority in the Senate but the Democrats were on course to regain control of the House, which could impact Donald Trump's legislative agenda.
But, while the vote is the first major electoral test of Trump's presidency, analysts pointed out the poll is unlikely to lead to a reversal of the White House's popular tax cuts and deregulation.
Nor will it wind in his aggressive efforts to reframe international trade, which has been a key to recent volatility in global markets.
"Equities remain supported suggesting this outcome is positive for risk since the gridlock outcome ultimately will support the president's mandate and a higher probability of more fiscal stimulus," said Stephen Innes, head of Asia-Pacific trading at OANDA.
"Realistically I can't see how the Democrats would want to be perceived as killjoys and try to stifle any policy which is supporting the economy," he added.
The vote has the added twist of a probe looking at whether Trump's campaign colluded with Russia to win the 2016 election.
If the Democrats win one house of congress, it would likely lead to extensive investigation of Trump's administration, creating new roadblocks for his agenda.
Hong Kong jumped more than one percent going into the break while Shanghai was up 0.3 percent and Tokyo added 0.7 percent.
Sydney added 0.2 percent, with Singapore and Seoul each 0.5 percent up. There were also gains in Taipei and Wellington but Manila and Jakarta were down.
On currency markets the dollar dipped against its major peers as well as higher-yielding and emerging market units, as a win for Republicans in both houses of Congress would likely have led to more tax cuts and regulatory measures.
- Brexit hopes -
The pound continued to rise as traders grew optimistic that officials are close to an agreement for a post-Brexit deal for Britain, with the question of Northern Ireland the main sticking point.
"With the smoke surrounding a possible Brexit deal thickening, the trading market looks justified in taking the view there must be a fire somewhere," said Ray Attrill, head of forex strategy at National Australia Bank.
Energy firms dropped with oil prices on worries about an oversupply following a forecast-beating rise in US stockpiles, while the head of the International Energy Agency called on OPEC to boost output.
The comment from director Fatih Birol comes as Venezuela's production dries up and US sanctions on Iran kick in.
However, the commodity was already depressed by news that Washington had given waivers to eight countries allowing them to continue buying crude from Tehran, tempering most of the embargo's impact.
"At least three of the top five consumers of Iranian crude have been granted waivers. Therefore the impact is likely to be substantially muted," Sukrit Vijayakar, founder of energy consultancy Trifecta Consultants, told AFP.
"Apparently, President Trump had a more important short-term goal of bringing oil prices down so as to help the re-election of Republican congressmen."
Both main contracts are down about a fifth from their four-year highs touched at the start of last month.
Key figures around 0420 GMT
Tokyo - Nikkei 225: UP 0.7 percent at 22,290.97
Hong Kong - Hang Seng: UP 1.2 percent at 26,427.31 (break)
Shanghai - Composite: UP 0.3 percent at 2,666.28 (break)
Euro/dollar: UP at $1.1457 from $1.1416 at 2120 GMT
Pound/dollar: UP at $1.3134 from $1.3097
Dollar/yen: DOWN at 113.29 yen from 113.46 yen
Oil - West Texas Intermediate: DOWN 26 cents at $61.95 per barrel
Oil - Brent Crude: DOWN seven cents at $72.06 per barrel
New York - Dow: UP 0.7 percent at 25,635.01 (close)
London - FTSE 100: DOWN 0.9 percent at 7,040.68 (close