Netflix added nearly seven million new customers in the three months to September, bringing its total to more than 137 million members worldwide.
The growth was stronger than expected, prompting the firm's shares to jump more than 10% in after-hours trade.
It came as the firm premiered a record amount of original programming, including new seasons of Orange Is The New Black and BoJack Horseman.
Netflix is among the first of the major US tech firms to report earnings.
Investors were looking for signs of a rebound at the company after an unusually weak second quarter, which had fanned worries about the online streaming firm's future.
Netflix faces increased competition from traditional media companies and giants such as Amazon and its costs have been growing as it invests in its own material.
The firm has said it plans to spend as much as $8bn on content this year, with more than a quarter devoted to original programming.
Analysts estimate that it added about 676 hours of original programming in the US in the most recent quarter, 135% more than in the same period a year earlier.
"We recognise we are making huge cash investments in content, and we want to assure our investors that we have the same high confidence in the underlying economics as our cash investments in the past," it said in a letter to investors.
Netflix had told investors it expected to add about five million members in the quarter.
The actual total - which included about one million new subscribers in the US and almost 5.9 million abroad - set a record for the third quarter, Netflix said.
Netflix revenue in the quarter increased 34% year-on-year to nearly $4bn, while profits more than tripled to $403m.