Mr. Ertel had been the supervisor of elections for Seminole County since February 2005 when Mr. DeSantis, a Republican, appointed him secretary of state in December. Before resigning, he had testified before a state legislative committee on Thursday about election lawsuits. As part of his duties as secretary of state, Mr. Ertel was in charge of the state’s effort to restore voting rights to 1.4 million ex-felons, which Florida voters approved in November. Mr. Ertel, who said he was homeless for a short time as a teenager, became an elections supervisor after a career in public relations that included work for Florida’s tourism industry. He served in the Army, doing public affairs work for the service. He is married with two adult children.