Mister Halling is one of the many miners who live in the Frontier Mining Town of Youswell and, due to his amicable and clear-headed nature, has been chosen by the Youswell mining community to be their unofficial chief and spokesman in their ongoing (albeit fruitless) negotiations with the landowner of Youswell - Lieutenant Yoki.
As a result of Yoki's exorbitant property taxes, Halling (along with many other Youswell residents) runs a tavern with his wife and his son Kyle partly as a place where the tired laborers of the town can rest and unwind after a hard day in the coal mines, but mostly as a way to bilk tourists out of their money with an admittedly unreasonable 200,000 cenz per night fee so as to keep up with Yoki's equally unreasonable demands. He is a friendly and kindhearted man, described by his friends and family as someone who will gladly take a loss if he can help out an ailing friend by doing so.
He first appears when Alphonse and Edward Elric appear in Youswell on an assignment to survey the Coal Mines and takes an instant liking to the boys, admitting that he'd dabbled in alchemy as a youth, but lacked the necessary talent to continue. But when it becomes clear that Edward is a State Alchemist, Halling - along with the rest of the town - becomes suddenly cold toward him, expressing his great distaste for the State Military, due to Yoki's corruption and the way the Lieutenant's bribes have kept Youswell from receiving proper help and attention from the authorities, and especially for State Alchemists, who have turned their backs on the concept of "Be Thou For The People" to become "Dogs of the Military" - in essence, selling their souls for power.
Halling refuses to allow a State Alchemist houseroom in his tavern and promptly kicks him out, though expresses further disgust when Yoki himself pays a visit, announcing yet another salary cut and gladly accepting Edward into his mansion for the night. When Yoki, angered at Halling's resistance on behalf of the town, orders that his tavern be burnt down during the night, Halling refuses to let Kyle and the other miners attack Yoki in revenge because he doesn't want them to become criminals and give Yoki more excuses to act. But all is solved when Edward returns, having cheated Yoki out of the deed to the town and "sells" it to Halling for 200,000 cenz, to be exchanged in the form of a night's stay in the tavern. With this, Yoki's leverage in Youswell is erased and Halling's faith in State Alchemists is restored.
The Envoy From the East
Halling appears again in Chapter 32 of the manga, when Mei Chang arrives in Youswell from Xing. Immediately after her encounter with Kyle, Youswell's Mine #8 collapses, trapping Halling and several other miners inside. They are rescued by Mei, who uses Xingese Alchemy to repair the mine in a flash, and spend the night thanking her with one of their rowdy parties. Halling mentioned to the xingese girl that this is the second time he has been rescued by an alchemist and tells her the tale of Edward Elric. Mei falls in love with Halling's description of the Fullmetal Alchemist and departs immediately, but as she leaves, Halling and Khayal note that they had forgotten to tell her how short Ed is.