Futabasha was founded in 1948 and though its longest-running and first major magazine debuted in 1958, the publisher's first major manga magazine (Weekly Manga Action) only began in 1967. Always aimed at the adult male demographic (in a time when seinen manga was much less prevalent), the first issue included the debut of what became one of the publisher's biggest franchises (Lupin III). Other major series soon followed including Kozure Ōkami (translated to English decades later as Lone Wolf and Cub), Jarinko Chie and Kariage-kun.
Another of the biggest franchises for the publisher, Crayon Shin-chan, was also originally serialized in the seinen Manga Action but due to its success, it managed to spin-off into a 4koma specialized magazine, Manga Town, which took over some of Manga Action's serials including Shin-chan.
Though Manga Action briefly ended in 2003, it started back up in 2004 to return as the publisher's primary manga magazine (but now only a biweekly). Since the 90's, Manga Action has even spun-out a line of hentai manga magazines (Action Pizazz) and in recent years, a more traditional spin-off magazine in Monthly Action.
Even the publishers limited focus on the female demographic for manga (Jour: Suteki na Shufutachi) is primarily focused around a magazine for adult females (josei) rather than the more popular shojo demographic.
Futabasha did briefly try to get their own Weekly Shonen magazine in the 70's (Weekly Shonen Action), which even included a shonen spin-off of the popular Lupin III franchise but the magazine was cancelled after a year.