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.
Soviet space program
While the government and the Communist Party used the program's successes as propaganda tools after they occurred, systematic plans for missions based on political reasons were rare, one exception being Valentina Tereshkova, the first woman in space, on Vostok 6 in 1963. Missions were planned based on rocket availability or ad hoc reasons, rather than scientific purposes. For example, the government in February 1962 abruptly ordered an ambitious mission involving two Vostoks simultaneously in orbit launched "in ten days time" to obscure John Glenn's Mercury-Atlas 6 that month; the program could not do so until August, with Vostok 3 and Vostok 4.