The dollar index was last up 0.4 percent at 84.362, on pace for its best daily gain in nearly two weeks.
The greenback was up 0.2 percent to 108.86 yen after scaling a six-year high at 109.45 yen.
Sterling is the other big currency mover in the market, jumping to a two-week high against the dollar and a two-year peak versus the euro, after Scotland voted to stay within the United Kingdom in a historic referendum.
However, the pound fell back on profit-taking during New York trading.
Analysts pointed to risk factors like promises for more powers to Scotland that could open up the prospects for some constitutional changes to next May's general election as risk factors for the pound. These could add some uncertainty to UK growth prospects and tie sterling down in the near term.
Earlier, sterling jumped to $1.6525 in Asian trade, its highest since Sept. 2. It was last down 0.4 percent at $1.6385.
Sterling eased from a two-year high of 78.10 pence per euro to trade at 78.52 pence per euro. It had also hit a six-year high against the yen, before slipping back.