“Rocky” gave audiences an underdog story for the ages, “Chuck” serves as a reminder that not all champions are larger than life.

Philippe Falardeau’s biopic examines an episode in the life and career of Chuck Wepner (Liev Schreiber), the professional boxer from Bayonne, New Jersey, rumored to have been the inspiration for Sylvester Stallone’s classic 1976 boxing film. “Rocky” offered plenty of epic training montages and dramatic dialogue to keep viewers glued to the screen, but “Chuck” doesn’t pad its hero’s story with clichés or cinematic extravagance. While its bluntness and sincere character exploration make it a refreshing film, they regrettably also make it a boring one.

“Chuck” centers around Wepner’s life leading up to and following his 1975 fight against Muhammad Ali, who was at his competitive peak at the time; Wepner’s struggle and close defeat undoubtedly reflect the Balboa-Creed match in “Rocky.” Unlike traditional boxing films, the “big fight” isn’t the film’s climax — it is merely the impetus for ensuing events, as the audience then witnesses Wepner’s attempts to grapple with his heightened fame following the match.

The film isn’t about Wepner’s extensive training or battle against the odds; it’s about his infidelity, his strained relationships and his substance abuse and his struggle to rebuild himself. Wepner is presented as a thoroughly flawed human being, and becomes an interesting, approachable protagonist for the blatantly realist film.

Still, Falardeau doesn’t pretend to distance “Chuck” from “Rocky.” Instead, he embraces the influence that “Rocky” had on Wepner’s life. The first shot opens up with a quote from Balboa, leading into the narration: “My name is Chuck Wepner … you do know me, but you don’t know you know me.”

The film explores Wepner’s reception of the tremendous success of “Rocky,” as well as his efforts to sustain his fame by befriending Stallone (Morgan Spector) and treading into Hollywood. The self-aware, referential tone carries the film but prohibits “Chuck” from occupying a uniquely creative or entertaining space. Outside the boxing ring the movie tends to drag, especially because the script relies less on plot than it does on its character arcs.

At the heart of the character-driven anecdote that is “Chuck” lies an exceptional performance by Schreiber. The actor is unrecognizable underneath all the prosthetics, but brings a casual ruggedness to his narration and portrayal. From his failing relationship with his wife Phyllis (Elisabeth Moss), to his brief and bloody encounter with Ali in the ring, to his attempts at grappling with short-lived fame following the fight, Schreiber is constant and convincing. He never moves beyond the emotional restraint that the role requires, making Wepner a real, flawed human being. Unlike Rocky Balboa, Chuck Wepner isn’t always easy to root for.

In addition to Schreiber, the supporting cast features a multitude of familiar faces (Ron Perlman, Jim Gaffigan, Naomi Watts) who are effective but unremarkable in their roles. However, Elisabeth Moss, portraying Phyllis in her loving support to her utter exhaustion in her marriage, is magnetic. This isn’t her first time building a character out of 20th century nostalgia (don’t forget “Mad Men”), but Moss is unwavering and sincere, even in an underwritten part.

“Chuck” relies on recreating 1970s aesthetics, and it does so effectively. Makeup and costuming transform and transport actors back to the era, and sets, filled with vintage patterns and vibrant lights, make for convincing backdrops to Wepner’s journey. The score stays consistent with the unpretentious tone by ditching dramatics for funk, jazz and disco, and “You Always Hurt the One You Love” is cleverly played over both a fight scene and an image of Wepner on a romantic stroll along the boardwalk.

While “Chuck” is an admirable attempt at a biopic of a largely unrecognized figure, it lacks the emotional depth and satisfaction that even the most clichéd boxing films manage to capture. Like “Rocky,” it’s an effective portrayal of an unlikely champion who must surmount his obstacles. But unlike “Rocky,” it’s not worth more than a one-time watch.