[2] Curtis served in the United States Naval Reserve from 1953 to 1955[3] and was a lieutenant commander in the Korean War before leaving the Navy to pursue a law degree.

Curtis's political career began in 1956 when he worked for James Oliver's Democratic campaign for Maine's 1st congressional district.

[3] In 1963, Curtis was appointed Maine Coordinator for the Area Redevelopment Administration by President John F. Kennedy and served in that position until 1964[3][4] when he campaigned for the 1st district seat but narrowly lost to Stan Tupper.

[5] In February 1970 Curtis announced his re-election bid, [1] defeating Plato Truman In the Democratic primary and faced Maine Attorney General James Erwin In the general election, Initially the underdog Curtis managed to gain momentum following a strong debate performance, [2] the campaign had boiled down basically to an issue of economy in state government, Erwin asserted that 10 per cent cut could be made in the state budget without hurting services.

[5] In 1969, Curtis and the Republican legislature enacted Maine's first income tax, which as of 2021 still provides the bulk of the state's revenue.

Curtis proposed gun control legislation, which would deny ownership to convicted felons, drug addicts, and those in mental institutions.

[5] In November 1971 Curtis made an 11th‐hour appeal urging voters to reject a referendum aimed at repealing the state's two‐year‐old income tax.

[7] in June 1973 Curtis signed a bill that eliminated the state's criminal penalties for knowingly being present where marijuana is kept.

[5] in December 1973 Curtis asked Maine residents in a televised address to voluntarily reduce their consumption of gasoline, heating oil and kerosene.

On Tuesday, July 20, 1970, Susan died at Central Maine General Hospital in Lewiston of respiratory failure.

Since Ken Curtis was serving his first term as governor, the family received numerous monetary donations in Susan's name, and friends and political supporters encouraged the Curtises to start a nonprofit organization with the funds.