According to market researcher Strategy Analytics, Samsung accounted for 33.7 per cent in the US smartphone market in the July-September period, up 6.7 per cent points from a year earlier, reports Yonhap news agency.
Apple was the runner-up with a 30.2 per cent share, followed by South Korean smartphone maker LG Electronics with a 14.7 per cent share.
This is the first time since the second quarter of 2017 that Samsung topped the US smartphone market.
Solid sales of its mid-tier and budget smartphones, along with launch of flagship devices, like the Galaxy Note 20 and Galaxy Z Fold2, apparently boosted Samsung's presence in the US.
Industry insiders said the late launch of Apple's iPhone 12 series may have also helped Samsung to thrive in the US.
Apple usually releases a new iPhone in September, but this year, the US tech titan began to sell new smartphones from October.
Samsung was also the leading vendor in the global smartphone market in the third quarter of the year with a 21.9 per cent share, beating China brands Huawei Technologies with a 14.1 per cent share and Xiaomi with a 12.7 per cent share.
Apple had 11.9 per cent market share in the global market in the third quarter.