In 1876, Sen. Morrill was appointed U.S. Secretary of the Treasury by President Grant, to fill in a vacancy after Sec. Benjamin Bristow resigned from office. His political rival James G. Blaine was appointed Maine's Senator after Morrill resigned from the Senate to accept the position of Secretary of Treasury. Morrill's tenure was less than a year. Upon his retirement from the Treasury Department, President Rutherford B. Hayes appointed Morrill to the Collector of Customs in Portland, Maine, where he held this position until his death in 1883.