"It was a glorious mission, full of challenges with a successful end," Zhai said after the Shenzhou 7 module landed under clear skies in the grasslands of China's northern Inner Mongolia region. "We feel proud of the motherland."
State broadcaster CCTV showed the astronauts emerge from their capsule, which floated gently down under a giant red-and-white-striped parachute, and wave at cameras as they celebrated the end of their 68-hour mission.
Zhai, Liu Boming and Jing Haipeng stayed inside for about 46 minutes to adapt to Earth's gravity before crawling out of the narrow entrance. They were declared healthy after medical examinations inside the module.
"This mission's success is a milestone; a stride forward," Premier Wen Jiabao said at mission control.
Saturday's space walk, which was broadcast live and watched by crowds gathered around outdoor television screens, further stoked national pride one month after the close of the Beijing Olympics.
"A small step by Zhai Zhigang in space is a big step in the history of the Chinese nation," said a commentary by the official Xinhua News Agency carried Sunday by the Beijing Daily newspaper.
On most newspaper front pages were pictures of Zhai clutching a Chinese flag as he hovered in space outside the Shenzhou 7 vessel, alongside photos of Chinese President Hu Jintao on a telephone as he spoke to the astronauts.
While successful, the spacewalk wasn't without anxious moments.
Zhai, a 41-year-old fighter pilot, appeared to struggle with the hatch and a fire alarm was triggered in the orbiter as he began the spacewalk.
Wang Zhaoyao, deputy director of manned space flight, conceded that the combined effects of weightlessness and depressurization on the hatch opening operation hadn't been fully anticipated. He blamed a faulty sensor for the fire alarm.
The spacewalk required the astronauts to first depressurize and then repressurize the orbital module and proved the effectiveness of Zhai's Feitian space suit, produced by China at a cost of $4.4 million. Liu wore a nearly identical Russian-made Orlan suit, according to the reports.
The spacewalk paves the way for assembling a space station from two Shenzhou orbital modules, the next major goal of China's manned spaceflight program.
China is also pursuing lunar exploration and may attempt to land a man on the moon in the next decade - possibly ahead of NASA's 2020 target date for returning to the moon.
China launched its first manned mission, Shenzhou 5, in 2003, becoming only the third country after Russia and the United States to launch a man into space. That was followed by a two-man mission in 2005.