Travelport completed a top-of-the-range listing that valued its equity at more than $2 billion (£1.2 billion), or $4.3 billion including its debt.
Its share price surged 11% as the technology company made its debut on the New York Stock Exchange.
The company raised nearly $500 million and will use the proceeds to reduce its debt to around $2.4 billion.
The IPO comes four years after Travelport pulled its London flotation.
Chief executive Gordon Wilson defended the decision to float in the US by pointing out that most of its shareholders were based there and that it had a data centre in Atlanta.
“The world has moved on,” he told the Times.
Wilson said that he was comfortable with a debt level of four times earnings because of the level of cash the company generates.
He said that Travelport would consider small acquisitions but ruled out a move for lastminute.com, which has been put on the market by rival Sabre.
“I buy things I can make money off,” he said.
Travelport sold its stake in Orbitz, owner of eBookers, this year.
Travelport’s first-half revenues rose by 4% to $1.1 billion and it made a pre-tax profit of $3 million, compared with a $98 million loss in the same period last year.