Posts by Eric Watson from the Bradley County police department in the state of Tennessee prompted a lawsuit supported by the American Atheists organisation.
Responding to the legal case and referencing one particular post where he referred to The Resurrection, Mr Watson said: "That post reflects my faith which is founded on the belief that Jesus Christ died for my sins and the sins of mankind."
The Bradley County Sheriff's Office will now pay $15,000 in damages to an anonymous plaintiff and American Atheists, as well as legal costs of $26,000.
Amanda Knief, National Legal and Public Policy Director of American Atheists, said: "This settlement is a clear win for the plaintiffs, whose First Amendment rights to free speech and to be free of government establishment of religion were infringed upon.
"We are pleased the sheriff has agreed to do the right thing by no longer using this official government social media account to promote religion."
Sheriff Watson is permitted to keep a personal Facebook page which is clearly identified as containing solely his personal opinions and not those of the department.