Green’s Dictionary of Slang

(US) cheerful, happy.

[1789		N. Webster Dissertations on the Eng. Lang. n.p.: This word is wholly lost except in New England. It is there used for comfortably, bravely, cheerful, as when one inquires about a sick person, it is said, he is chirk].
1833		C.A. Davis Letters of Major J. Downing (1835) 31: Afore I had mixed a second glass of switchel, up they came, and the General looked as chirk and lively as a skipper.
1844		‘Jonathan Slick’ High Life in N.Y. I 196: I [...] pulled foot for Cousin Beebe’s as chirk as a grass-hopper.
1857		Knickerbocker (N.Y.) xlix (Feb.) 182: The old man gave us a good feed, and told us to look as chirk and lively as we could.
1878		R.T. Cooke Happy Dodd Ch. xxvii: I didn’t feel real cherk this week, so ’t I didn’t go to sewin’.
1891		Eve. World (NY) 18 Dec. 4/3: Jim was chirkyas you please.
1910		N.Y. Tribune 18 Sept. 6/2: Made me feel bright and chirky, just to see ’em there, so [...] I cut loose with some real cute joshes.
1915		S. Ford Shorty McCabe on the Job (2007) 11: He comes in smilin’ and chirky.
1915		S. Ford Torchy, Private Sec. 17: I’m left feelin’ all warmed up and chirky.
1918		Sun (NY) 14 Sept. section 6 7/3: He’s safe inside his fort [...] Chirky, clean an’ stout!