John Aaron Christianson (November 23, 1923 – December 15, 2010 He was educated at the University of Manitoba, earning a Bachelor of Science degree in Mechanical Engineering. He worked as an automobile and implement agent, and was the president of Christianson Ltd. and Koko Platz Development Ltd. From 1942 to 1945, he served as a pilot in the Royal Canadian Air Force. Concurrent with his career in provincial politics, he was a city alderman in Portage la Prairie in 1959-60.
He was elected to the Manitoba legislature in the 1959 provincial election, defeating incumbent Liberal-Progressive Charles Greenlay by 473 votes in the Portage la Prairie constituency. He was appointed to Roblin's cabinet on October 25, 1961 as Minister of Welfare.
Christianson's time in office was brief, as he narrowly lost his seat to Liberal candidate Gordon Johnston in the 1962 election. He formally resigned from cabinet on February 27, 1963.