Green’s Dictionary of Slang

a derog. term for a black person, usu. a freed slave.

1862		Dly Jrnl (Montpelier, VT) 26 Apr. 3/2: ‘I’m no Yankee,’ replied Ned indignantly. ‘Yes, you are,’ rejoined Harry; ‘you are a smoked Yankee’.
1876		Pioche Record (NV) 10 Feb. 2/3: Someone twitted him with being a ‘nigger,’ when he said: ‘Go way; I’se no nigger; I’se a smoked Yankee’.
1888		Melvin Grigsby Smoked Yank (1891) 92: The line on either side was a line of living, human skeletons [...] not exactly smoked Yankees, but the smoked skeletons of Yanks [DA].
1898		Hartford Courant (CT) 24 Sept. 12/1: These colored men, whom the Spaniards dubbed ‘smoked Yankees’.
1900		Denton Jrnl (MD) 25 Aug. 2/2: Teddy Roosevelt [...] calls the colored troops ‘smoked Yankees’.
1910		Topeka Dly Capital (KS) 4 Dec. 23/2: The next man to bat was Samuel the ‘Smoked Yankee,’ still considerably soused.
1918		Anaconda Standard (MT) 3 Oct. 10/6: ‘Boy, whah you co’ from? asked the smoked Yankee, pleasantly.
1924		People’s Herald (Quenemo, KS) 18 Sept. 1/2: They are [pretty sure in their own minds that there is [...] a smoked yankee in the woodpile.
1949		J. Monaghan This is Illinois 84: Hundreds of freed slaves—‘smoked Yankees’—followed the armies [DA].
1983		(con. 1820s) Irving L. Allen Lang. of Ethnic Conflict 47: Color Allusions, Other than ‘Black’ and ‘Negro’: […] smoked-yankee [1820s. A freed black].