 He was a member of the New York State Assembly (Oswego Co., 1st D.) in 1853, 1854, 1855, 1857, 1859, 1860, 1861, 1866, 1867, 1870, 1871 and 1884.He was Speaker in 1855, 1857, 1859, 1860 and 1861; and was the chief lieutenant of political boss Thurlow Weed.Early in 1861, Littlejohn was influential in the backroom politics to select Ira Harris over Horace Greeley as the Republican Party's nominee to run for the U.S. Senate to succeed William H. Seward, who had not run for re-election, expecting to join President Abraham Lincoln's Cabinet.