Ninebot's CEO Gao Lufeng said the U.S. company is an influential brand, with a strong patent portfolio and market presence.
"With the two brands together we will have a lot of resources," Gao said at a news conference in Beijing.
Segway president Rod Keller sent a videotaped message, saying: "Today, Segway became a part of the Ninebot family."
With the acquisition, Ninebot's payroll will grow from 400 to 500. The deal will pave the way for Ninebot's international expansion in the personal transporter market. Segway will act as a subsidiary of Ninebot, which will use both brands, it said.
The companies haven't always been this close: Last year, Segway filed a complaint against Ninebot with the U.S. International Trade Commission, alleging that Ninebot had infringed on its patents.
"It seemed like we were facing a competitor that was tough to beat," Gao said.
The companies began negotiating the acquisition in October. They didn't reveal the terms of the deal, although Gao said the price would make someone go "wow."
Ninebot also announced Wednesday that it has received new investments totalling $80 million from Chinese handset manufacturer Xiaomi and other investment firms.
Xiaomi CEO Lei Jun said he supported the acquisition, and Ninebot's effort to become an international brand. His company is hoping to accomplish the same, and is expanding into markets across Asia.
"Xiaomi's strategy is to push development in smart hardware and in the Internet of Things, and then connect them with the smartphone," he said.
Ninebot's CEO added that he hopes to collaborate with Xiaomi on product integration.