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.
Shannon Lucid
Lucid is best known for her fifth spaceflight, when she spent 188 days in space, from March 22 to September 26, 1996, including 179 days aboard "Mir", the Russian space station. Both to and from Mir, she travelled on Space Shuttle Atlantis, launching on STS-76 and returning on STS-79. Her stay on Mir was not expected to last so long but her return was delayed twice, extending her stay by about six weeks. During the mission she performed numerous life science and physical science experiments. As a result of her time aboard Mir, she held the record for the most hours in orbit by a non-Russian and most hours in orbit by a woman. On June 16, 2007, her record for longest duration spaceflight by a woman was exceeded by Sunita Williams aboard the International Space Station.