He was a scion of an old French noble family dating back the reign of Saint Louis, which gave the ancient city of Toulouse a Capitoul during the Middle Ages.
As numerous young ambitious provinciaux eagerly wanting literary fame and fortune, he migrated to Paris with the support of his uncle, the then already famous sculptor Aristide Maillol.
Jean de La Hire is remembered nowadays mainly for having created one of the first literary superheroes of so-called pulp fiction: The Nyctalope, Leo Saint-Clair.
The real Nyctalope appeared for the first time in Le Mystère des XV (1911) and continued to be published until the mid-1950s, when its books were reprinted by La Hire's son-in-law as rewritten editions.
In 1940 he published an anti-French and pro-Nazi volume, Le Crime des évacuations; Les Horreurs que nous avons vues, in which he praised the Nazis for their helpfulness to the French war refugees.