Astronaut
The first civilian in space was Valentina Tereshkova aboard Vostok 6 (she also became the first woman in space on that mission).
Tereshkova was only honorarily inducted into the USSR's Air Force, which did not accept female pilots at that time. A month later, Joseph Albert Walker became the first American civilian in space when his X-15 Flight 90 crossed the line, qualifying him by the international definition of spaceflight. Walker had joined the US Army Air Force but was not a member during his flight. 
The first people in space who had never been a member of any country's armed forces were both Konstantin Feoktistov and Boris Yegorov aboard Voskhod 1.
Timeline of space travel by nationality
Since the first human spaceflight by the Soviet Union, citizens of 40 countries have flown in space. For each nationality, the launch date of the first mission is listed. The list is based on the nationality of the person at the time of the launch. Only 3 of the 40 "first flyers" have been women (Helen Sharman for the United Kingdom in 1991, Anousheh Ansari for Iran in 2006, and Yi So-yeon for South Korea in 2008). Only three nations (Soviet Union/Russia, U.S., China) have launched their own manned spacecraft, with the Soviets/Russians and the American programs providing rides to other nations' astronauts. Twenty-six "first flights" occurred on Soviet or Russian flights while the United States carried thirteen.