Pete Hegseth described as "good and constructive" his meeting with Chinese Admiral Dong Jun, held on the sidelines of the Association of Southeast Asian Nations defence ministers meeting in Kuala Lumpur, Malaysia.
He said he raised US concerns over Chinese activities in the South China Sea, around Taiwan and towards US allies and partners in the region.
"I highlighted the importance of maintaining a balance of power in the Indo-Pacific," Hegseth wrote on social media platform X.
"United States does not seek conflict (but) it will continue to stoutly defend its interests and ensure it has the capabilities in the region to do so."
China's defence ministry issued a cautious response, emphasising its longstanding positions.
Dong Jun stressed the reunification of China and Taiwan was an "unstoppable historical trend" and urged the US to be cautious in its words and actions on the Taiwan issue, the statement said.
"We hope the US will translate its statements of not containing China and not seeking conflict into action, and work with China to inject positive energy into regional and global peace and security," according to the statement.
Their meeting follows a September 9 video call between Hegseth and Dong and reflects ongoing efforts to manage tensions in the Indo-Pacific even as strategic differences, particularly over Taiwan and freedom of navigation, remain pronounced.
Hegseth also met India's Defence Minister Rajnath Singh, and they signed a 10-year framework aimed at expanding military and technological co-operation.
Washington has long sought to develop a deeper partnership with New Delhi, which is seen as a bulwark against China. India is a major defence partner of the US and has in recent years embedded advanced American jets, helicopters, missiles and military gear into its armed forces.
Singh said the US-India partnership is crucial for ensuring a free, open and rules-based Indo-Pacific region.
"It is a signal of our growing strategic convergence and will herald a new decade of partnership," he said on X.
The framework agreement comes amid renewed strains in bilateral ties after President Donald Trump imposed a 50 per cent import tariff on Indian goods in August and criticised New Delhi for continued purchase of discounted Russian oil.
India is the second-biggest buyer of Russian oil after China.
Hegseth also held talks with his Malaysian counterpart on Thursday, where they reaffirmed their commitment to maritime security in the South China Sea.
Opening the ASEAN defence ministers meeting, Mohamed Khaled Nordin warned that regional peace faced growing pressure from both traditional and emerging threats, including rising tensions in the disputed South China Sea and the spread of cyberattacks that can "disrupt societies, topple governments and undermine critical infrastructure".
ASEAN defence ministers will continue talks Saturday with dialogue partners including the United States, China, Japan, India, Australia, South Korea and Russia.
