Career
During his time in office he served as a cabinet minister in the government of Harry Strom from 1969 to 1971. Henderson ran for a seat to the Alberta Legislature in the 1963 Alberta general election. He ran in a hotly contested race in the electoral district of Leduc against five other candidates.
The election results were heavily divided with no candidate winning a clear majority.
Henderson ran for a second term in the 1967 Alberta general election. Henderson was appointed as a Commissioner of Oaths on October 24, 1967.
He was appointed to the Executive Council of Alberta by Premier Harry Strom as Minister of Health and Minister of the Environment. The 1971 boundary redistribution would see the Leduc electoral district abolished.
Henderson ran in the new electoral district of Wetaskiwin-Leduc for the election held that year.
He held his seat by a narrow margin against Progressive Conservative candidate Emanuel Pyrcz. However, the Social Cr government led by Harry Strom was defeated and Henderson and the remaining Social Cr MLAs moved to the Opposition benches. Werner Schmidt became party leader in 1973 but did not have a seat in the legislature.
Henderson was recognized as the Leader of the Opposition for a portion of 1973 but then quit the party and sat as an Independent.
Henderson retired at dissolution of the assembly in 1975.