<P> A total of 113 Justices have served on the Supreme Court of the United States, the highest judicial body in the United States . Justices have life tenure, and so they serve until they die in office, resign or retire, or are impeached and removed from office (which has never happened; the one impeached Justice was acquitted). Among the current members of the Court, Associate Justice Anthony Kennedy is the longest - serving justice, with a tenure of 7004110440000000000 ♠ 11,044 days (7004110440000000000 ♠ 30 years, 86 days) as of May 15, 2018 . For the 104 non-incumbent justices, the mean length of service was 6,112 days (16.7 years) with a standard deviation of 3,620 days (9.9 years). The median length of service was 5,740 days (15.7 years). Their period of service ranges from William O. Douglas's 13,358 days (7004133580000000000 ♠ 36 years, 209 days) on the Court to the 163 - day tenure of Thomas Johnson . </P> <P> The table below ranks all United States Supreme Court Justices by time in office . The basis of the ranking is the difference between dates; if counted by number of calendar days all the figures would be one greater, with the exception of Charles Evans Hughes and John Rutledge, who would receive two days each . </P>

Who is the longest serving justice currently on the supreme court