The IPO raised $731.5 million, after the initial public offering of nearly 36.6 million shares was priced above the expected range.
The company on Tuesday expected the IPO to be priced between $17 and $19 per share, for an offering of 34.5 million shares.
Fitbit makes both wrist bands and clippable devices that monitor fitness activity by tracking calories burned or distance covered, among other things.
Fitbit said it held an 85% share in the U.S. connected activity tracker market in the 1st quarter of 2015, on a dollar basis, citing research firm NPD Group.
Founded in 2007, Fitbit has reported sales of more than 20.8 million devices as of March 31, more than half of which were sold in 2014 alone.
Fitbit’s revenue nearly tripled to $745.4 million in 2014 from the previous year.
The company faces stiff competition from rivals such as Garmin, Jawbone and Misfit. But its biggest challenger could be the Apple Watch, which has a host of health-related features and apps.
Venture capital firm Foundry Group is the largest shareholder in San Francisco-based Fitbit, with a 28.9% stake.
The company’s shares are expected to start trading today on the New York Stock Exchange under the”FIT” symbol.
Morgan Stanley, Deutsche Bank Securities and Bank of America Merrill Lynch were among the underwriters for the offering.