Coughlin, who has represented Summit County in the Senate since 2001, has filed the necessary papers with the secretary of state to begin raising and spending money for a gubernatorial campaign.
Coughlin, 38, announced his candidacy on his Web site, saying, "The days when a handful of people in Columbus pick our candidates for us have come to an end."
Former U.S. Rep. John R. Kasich of Westerville also is considering a run for governor, but he has yet to form a campaign committee.
Kasich has been wooing support from GOP activists for more than a year, and during the next two months, he is scheduled to keynote about a dozen county party Lincoln Day dinners.