Mission commander Zhai Zhigang floated out of the orbiter module's hatch in the spacewalk, shown live on state broadcaster CCTV. Tethered to handles attached to the Shenzhou 7 ship's orbital module's exterior, Zhai remained outside for about 13 minutes before climbing back inside and closing the hatch behind him.
"Shenzhou 7 has left the module, physically feel very good. Greetings to all the people of the nation and all the people of the world," Zhai said.
Fellow astronaut Liu Boming also emerged briefly from the capsule to hand Zhai a Chinese flag that he waved for an exterior camera filming the event. The third crew member, Jing Haipeng, monitored the ship from inside the re-entry module.
Top Communist Party officials including President Hu Jintao watched the spacewalk from a Beijing command center, breaking into applause with the successful completion of each stage of the maneuver.
The successful 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.
In step with its growing list of achievements, the military-backed program has grown progressively less secretive and officials have hinted in recent days at a desire for greater cooperation with other nations. China plans to mass produce the next version of the Shenzhou ship to service a future space station and says it may make such missions available to other countries.
Space cooperation between China and other nations has so far been limited and the U.S. has refused Chinese involvement in the international space station for fear it could gain technical secrets applicable to its arms industry.
A Chinese space program official said earlier that Russian technicians would assist in Saturday's spacewalk, but it wasn't clear what role they played.
Since blasting off from their northwestern China launch base on Friday, the astronauts had been largely occupied with preparing the suits and adapting to zero gravity. Meals aboard the craft have followed a typical Chinese menu, featuring versions of kung pao chicken, shrimp and dried fruit, the official Xinhua News Agency said.
On Friday, the three-module capsule shifted from an oval orbit to a more stable circular orbit 213 miles above Earth, meaning it is circling at a constant distance.
The change ensured that Earth's gravitational pull would not vary during the spacewalk attempt and will help Shenzhou make a precise landing on the Inner Mongolian Steppe on Sunday after its re-entry vehicle bursts through Earth's atmosphere, Xinhua said.
Following the spacewalk, the craft is to release an 88-pound satellite which is to circle the orbiter and send back images to mission control.