From French Louis, from Middle French Loïs, Loïc, &c., from Old French Looïs, Luis, Lodhuvigs, Lodevis, Lodhwig, &c., from Latin Ludovicus, from Clodovicus, from Frankish *Hlūdawīg, from Proto-Germanic *hlūdaz (“loud; famous”) + *wīgą (“battle”).
Doublet of Lewis (which is inherited since the Middle Ages) and, more remotely, Aloysius, Luis, Ludwig, Luigi, and Clovis.