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.
Peggy Whitson
Peggy Whitson arrived at the International Space Station on November 19, 2016, on Expedition 50/51, which was launched on November 17, 2016, from the Baikonur cosmodrome in Kazakhstan. She became the commander of Expedition 51. With the launch of Expedition 50/51 with her on it, Whitson, at age 56, became the oldest woman to fly into space. During the mission, she broke the record for cumulative time spent in space by a U.S. astronaut, surpassing the previous record of 534 days set by Jeff Williams. In early April 2017, her mission was extended by an additional 3 months at the International Space Station. On September 3, she returned in a previously vacant seat on the Soyuz capsule accompanied by NASA's Jack Fischer and Fyodor Yurchikhin of Roscosmos.