“I’ll say to you what I said to your father,” says Albert Pierrepoint’s mother early in “Pierrepoint: The Last Hangman,” opening today at the IFC Center. “Don’t bring it over that threshold.”

The “it” is emotional baggage young Albert will likely accumulate by choosing to follow in the career footsteps of both his father and his uncle. Between 1932 and 1956 Pierrepoint worked his way from a gallows assistant to Britain’s chief executioner, carrying out the sentence of death by hanging for nearly 450 people.

Director Adrian Shergold and writers Jeff Pope and Bob Mills deserve credit for not offering standard-issue flashbacks as facile explanations for what made Pierrepoint the gifted and passionately committed killer of killers he became. Pierrepoint, the film suggests, saw his vocation not as a plug for a personal void or as a birthright, but as a sacred privilege.

In every execution the film depicts, Pierrepoint takes the task of shepherding his charges over their individual mortal thresholds very seriously indeed. Calculating the length of rope required to neatly sever the spine based on the condemned’s height, weight, and lifestyle, or working out ways to expedite the trip from holding cell to gallows to eternity, Pierrepoint courts customer satisfaction by making the business of state sanctioned killing as swift and as painless as possible.

Timothy Spall plays Pierrepoint with a circumspect yet earnest quality reminiscent of a precocious but gloomy child. His heavy eyebrows and permanent pouting frown cannot disguise the sparkling eyes of an open-hearted and gentle humanist convinced that death at his highly skilled hands neatly evens up the balance sheet and grants spiritual rehabilitation for the dead. “She paid the price,” Pierrepoint says to a callow assistant who fails to grasp the postmortem beauty in stripping and washing the corpse of a recently dispatched female murderer. “She’s innocent now.”

Until Pierrepoint’s time, the identities of Britain’s hangmen were kept a secret from the public. The hangman doesn’t even acknowledge the exact nature of his “business trips” to his wife Anne until several years into their marriage. But when he’s personally selected by Field Marshall Montgomery to hang some 200 Nazi war criminals, Pierrepoint is outed in the British press. Much to his discomfort, the executioner becomes an instant folk hero to a broke and angry nation in search of some validating closure to World War II.

Fame proves his undoing, or at least his eye-opening, as Anne (played with genial understatement by Juliet Stevenson) persuades him to open a pub to capitalize on his notoriety. But the only pride Pierrepoint permits himself continues to be that found in a job well done.

Any ironies and hypocrisies Pierrepoint discovers in the workplace or at home remain his alone to sort out. At the end of the day and at the end of a rope, it’s not the anti-capital punishment newspaper headlines and close-ups of speechifying reformers that prod the hangman into retirement, but a row of figures in a ledger book that call into question whether Pierrepoint’s bosses appreciate the quality of his work.

Mr. Shergold has rendered Pierrepoint’s life as a passably sturdy biopic awash in the same drab colors, tweedy textures, and pasty complexions of the dark British films of the 1960s and ’70s. And though the scripted Pierrepoint is a somewhat sanitized reduction of the considerably less wide-eyed and conflicted real thing, Mr. Spall successfully sells the strangely beguiling fantasy of a burly overgrown kid with his hand on the trap door lever who is trying to reconcile what his conscience tells him with what his father and his country have raised him to believe.