SAN FRANCISCO — Twitter continues to stabilize as a business.

The social media company on Thursday reported a 24 percent jump in fourth-quarter revenue from a year earlier, to $909 million, while its net income more than doubled to $255 million. After losing money for years, Twitter has now posted five straight quarters of profits, even though its revenue growth has slowed.

The financial performance was marred by a drop in Twitter users for a third consecutive quarter. The company said it had 321 million users in the fourth quarter, down from 326 million in the previous quarter.

Still, Jack Dorsey, Twitter’s chief executive, said the results indicated that his company was finding its financial footing — especially since it was the first full year that Twitter had turned a profit.

In a statement, he said “2018 is proof that our long-term strategy is working.”

Twitter, President Trump’s favorite social media service, has been grappling with challenges for some time, such as harassment and bullying on its platform. More recently, it has also had to deal with disinformation, foreign interference and accusations of political bias. Mr. Dorsey denied that Twitter was biased when he testified before Congress late last year.