Green’s Dictionary of Slang

(US) an astute, shrewd person.

1790		M.P. Andrews Better Late than Never 19: So, Mr. Longhead and Mr. Wronghead, you wise cabinet counsellors.
1837		John o’Groat’s Jrnl 6 Oct. 4/1: Longhead and Loggerhead opposed one another. ’Twas a glorious election [...] Longhead had the sense, But Loggerhead the pence.
1842		T.E. Hood University Feud in Works (1862) V 419: Or whether this here mobbing – as some longish heads foretell it, / Will grow to such a riot that the Oxford Blues must quell it.
1852		G.C. Mundy Our Antipodes I 102: That reprobate had a long head on those same fustigated shoulders.
1869		Western Times 22 June 2/4: Duke Wronghead and Lord Longhead.
1890		‘’Arry on Equality’ Punch 22 Feb. 85/2: Luck, Law, and the Longheads, / Have arranged the world.
1903		‘Dads Wayback’ in Sun. Times (Sydney) 2 Aug. 3/4: ‘Ter govern a country proper [...] brains is wanted — big long heads’.
1909		W. Irwin Confessions of a Con Man 39: He had a long, cool, scheming head and wonderful card sense.