Which astronaut was the first to complete a spacewalk?

The first astronaut to complete a spacewalk was Ed White, who performed this historic feat on June 3, 1965, during the Gemini 4 mission. A spacewalk, or extravehicular activity (EVA), involves an astronaut leaving the confines of a spacecraft to conduct activities in the vacuum of space. White's spacewalk lasted about 23 minutes and marked a significant milestone in space exploration, demonstrating the capabilities of astronauts to operate outside their spacecraft in the harsh environment of space.

Other options do not hold the distinction of being the first to conduct a spacewalk. For instance, while Alan Shepard was the first American in space, he did not perform a spacewalk; his flight took place before EVAs were conducted. John Young also made substantial contributions to space exploration but did not achieve the first spacewalk. George Clooney, being a fictional character and a film actor rather than an astronaut, is unrelated to the context of space exploration history.