Variant of Herman, from Germanic elements meaning 'army man' or 'soldier.'
Harmon descends from the Old High German name Herimann — a compound of "heri" (army, host of warriors) and "mann" (man) — making its root meaning something close to "man of the army" or "warrior." The name traveled into English as Herman and threw off numerous variant forms across medieval Europe; Harmon emerged as a distinctly English and later American adaptation, occupying the space between surname and given name with comfortable ease. It shares its etymological heartland with Harmony, though the two names diverged centuries ago.
As a surname, Harmon appears widely in Anglo-American history — most visibly in the twentieth century through American entertainer and bandleader Harmon Nelson and through the many Harmon families who pushed into the American frontier. The name lent itself naturally to the surname-as-first-name tradition that flourished in America from the colonial era onward, where family names were recycled as given names to honor maternal lineages or prominent neighbors. Mark Harmon, the actor best known for playing Leroy Jethro Gibbs on "NCIS," kept the name in quiet public view across four decades of American television.
Harmon occupies a pleasing sonic and cultural niche: it is strong without being aggressive, old-fashioned without being fusty, and carries a faint musical resonance (harmonic, harmony) that gives it a gentle sophistication. Parents today are drawn to it as an alternative to the more common Herman or the trendier Harrison, finding in Harmon something that sounds established rather than invented.