Kean lost by 84,545 votes, 966,832 (51.39%)to 882,287 (46.90%). Kean made a political comeback in 1959, challenging incumbent William Yeomans for Essex County Republican Chairman. Essex County Republicans were divided into two factions; Kean organized a slate of reform candidates opposed to Yeomans headed by Alfred C. Clapp, a popular former State Senator and Superior Court Judge. Yeomans backed Essex County Prosecutor Charles V. Webb, Jr. for the State Senate, but Clapp won the nomination by a massive 20,000 vote margin (72%-28%). All twelve Assembly candidates running on the Kean/Clapp line won the primary. Yeomans dropped his re-election bid, clearing the way for Kean to take over what was viewed as the most powerful Republican organization in the state. Among the political newcomers who ran on the Clapp ticket was C. Robert Sarcone. Kean had a tough time as a party leader. Democrats held the Essex County State Senate seat, with incumbent Donal C. Fox defeating Clapp in the General Election; Democrats won five of Essex County's twelve Assembly seats in 1959, and eight of the nine seats in 1961. Kean backed the losing candidate in the 1961 Republican gubernatorial primary, Bergen County State Senator Walter H. Jones. A Kean rival, former U.S. Attorney William F. Tompkins, challenged Kean for re-election in 1961 after Tompkins' candidate, former U.S. Secretary of Labor, James P. Mitchell, won the gubernatorial nomination. Kean beat Tompkins, 409 to 268. Kean stepped down as County Chairman in 1962 and endorsed former Livingston Mayor Andrew C. Axtell as his successor. Tompkins ran again, but Axtell beat him 438 to 416. Kean married Elizabeth Stuyvesant Howard on October 18, 1920, in New York City. Following the death of his uncle, Alexander Kean, in 1922, Kean inherited an estate and mansion in Livingston, New Jersey, where they moved in 1924. They had six children: three sons, Robert, Hamilton and Thomas, and three daughters, Elizabeth, Rose and Katharine. Kean died in Livingston on September 21, 1980, at Saint Barnabas Medical Center due to a heart attack. Kean University is named in honor of Robert Kean and the Kean family and its Liberty Hall Campus houses the historic property and home of the Kean family.