Fallin said Coffee brought a wealth of experience to the Capitol.
“He's mentioned to me several times that he's got to think about his family and his family's future and that he just wanted to serve as long as he felt like he could,” she said. “I've been very grateful for his service to the state of Oklahoma. ... I certainly understand that he's got family concerns he needs to take care of.”
Coffee is the second to leave Fallin's Cabinet. Oscar Jackson retired from state service and stepped down in September 2011 as secretary of human resources and administration.
Finance Secretary Preston Doerflinger will assume Coffee's responsibilities as Fallin's lead budget negotiator, the governor's office said.
Coffee also has been involved in talks aimed at resolving a federal lawsuit filed last year by the Chickasaw and Choctaw nations to stop Oklahoma's plans to draw water from Sardis Lake in Pushmataha County and deliver it to Oklahoma City.
The Fallin administration plans to retain Coffee as an outside consultant on water issues, although details of that arrangement have not been finalized, according to the governor's office.
The office of the secretary of state serves as a registry of Oklahoma's official documents, filing and certifying executive orders, appointments and proclamations as well as publishing new statutes.
“It's been a great opportunity, I've enjoyed it all,” Coffee said.