The head of Missouri's Office of Administration is stepping down effective Feb. 1.

Gov. Jay Nixon announced Tuesday that Administration Commissioner Kelvin Simmons was leaving the position. In a resignation letter dated Monday, Simmons said he was pursuing an "opportunity outside of state government" but did not elaborate.

Simmons has led Nixon's administrative office since Nixon became governor in 2009. In previous Democratic administrations, Simmons served as director of the Department of Economic Development and as chairman of the Missouri Public Service Commission, which regulates utilities. He got his start in state government in 1993 as director of the Office of Equal Opportunity.

Nixon said his deputy chief of staff, Doug Nelson, will serve as the acting commissioner of administration.

Send questions and comments about this story to feedback@stlpublicradio.org.