McLean, John (məklānˈ) [key], 1785–1861, American political figure and jurist, b. Morris co., N.J. His family moved to Ohio, where he studied law, was admitted (1807) to the bar, and practiced in Lebanon. He served in the House of Representatives (1813–16), was an associate justice of the Ohio supreme court (1816–22), and commissioner of the U.S. General Land Office (1822–23). President Monroe appointed him Postmaster General in 1823, and he was reappointed by John Quincy Adams. McLean resigned in 1829 because of disagreement with Andrew Jackson on the question of patronage. Jackson, however, appointed (1829) him to the U.S. Supreme Court where he served as an associate justice until his death; he is perhaps best remembered for his dissenting opinion in the Dred Scott Case.
See biography by F. P. Weisenburger (1937, repr. 1971).