Guerriere was launched on 9 September 1865 in the Boston Navy Yard and commissioned on 21 May 1867, Commander Thomas Corbin, in command. She sailed from New York on 28 June 1867 to serve as flagship of the South Atlantic Squadron protecting American commerce and interests along the coast of South America. She was relieved as flagship by Lancaster on 17 June 1869 and sailed from Rio de Janeiro the 25th for the New York Navy Yard where she decommissioned on 29 July 1869.