With memories of a frail and infirm Pope John Paul II still vivid, it takes some adjustment to accept a young Karol Wojtyla, here vigorously embodied by Polish actor Piotr Adamczyk.

But the moving “A Man Who Became Pope,” airing on cable’s Hallmark Channel Monday, Aug. 15, 8 p.m.-midnight EDT, is, in fact, an account of the early days of the young playwright-actor who turned priest in Poland, first under the brutal heel of the Nazis, and after the war the communists. (It will be rerun Sunday, Aug. 21, 9 a.m.-1 p.m. EDT.)

The story begins in 1939, with a reluctant Karol going off to war to protect his elderly father who is stubbornly determined to join the army over the family’s objections. One of Karol’s closest friends is the devoted and serious-minded Hania (former Avedon model Malgosia Bela). Her presence cannily provides the film with a leading lady, if not an actual romance. (“She’s like a sister to me,” Karol says.)

During the occupation, Hania helps hide a Jewish family, Anne Frank-style.

Karol and his father eventually return home, driven back by the deadly aerial bombardment of the Germans and a warning that the Russians are blocking the way.

The Nazis are personified by Governor-General Hans Frank (Matt Craven). Among many heinous acts, Frank closes the university, and interns the professors in camps. An outspoken professor (Kenneth Welsh) is summarily shot.

Stalwart Father Thomasz Zaleski (Raoul Bova), Karol’s childhood friend, bravely faces up to the occupiers, most dramatically when Frank orders Father Zaleski to dine with the Nazi brass who proceed to viciously denigrate the Polish people, until the priest, who can take it no longer, makes an impassioned defense, and defiantly walks out. Later, he’ll give absolution to a repentant Nazi, much to Karol’s initial dismay.

The atrocities that Karol witnesses seem to touch his very soul. “What is it that makes eyes, hearts and minds so incapable of feeling pity and respect?” he cries at one point.

The Nazis try to eradicate Polish culture, insisting that they had no heritage to begin with, and Karol’s theatrical troupe must perform underground.

When their close friends, resistance fighters Wiktor and Krystyna, are shot by the Nazis, Karol almost despairs until a mystic tailor tells him the importance of winning with love, not guns. This will be Karol’s mantra ever after.

As time passes, the world of the theater begins to seem “empty” to Karol, and he declares his vocation to the priesthood.

After the war, the Russian liberators are hailed by the Polish people as their salvation. But, in fact, they are as opposed to the church as the Nazis.

The villain of the second half is Comrade Kordek (Hristo Shopov, who played Pontius Pilate in “The Passion of the Christ”), the secret service agent who becomes Karol’s bete noire. Kordek resents Karol’s serene assurance and hires a spy, Adam Zielinski (Ken Duken), to wiretap Karol’s confessions in hopes of catching him criticizing the regime. He doesn’t want Karol teaching young people to have no fear: “If these people aren’t afraid of us, it’s all over.”

Adam enrolls at the university where Karol is now an ethics professor. One of Karol’s female students becomes smitten with Adam, but the dogged fellow continues his traitorous mission, yet fails to catch Karol speaking disloyally.

The film charts Karol’s rise in the church hierarchy, with his becoming auxiliary bishop, then bishop of Krakow, and finally, to his own humble amazement, pope. Seen in the context of what has come before, his election seems a fitting validation of a steadfast faith and noble life. (The events of the conclave are dispatched—rather hurriedly—in the movie’s last few minutes.)

This theatrical-quality production—Italian-made but filmed on location in Poland with a largely Polish cast—was based on Gian Franco Svidercoschi’s book “Stories of Karol: The Unknown Life of John Paul II.”

Pope Benedict XVI commended in June the film’s focus on Karol’s early heroism for “reviving in every right-minded person the duty to do what he or she can so that such inhuman barbarism never happens again.” He also discerned a “divine plan” in the ironic fact that a “Polish pope … (has been) succeeded by a citizen of that country, Germany, where the Nazi regime was the most vicious, attacking the nearby nations, Poland among them.”

“A Man Who Became Pope” was screened for Pope John Paul II shortly before his death and the pontiff was said by Vatican spokesman Joaquin Navarro-Valls to have been “very impressed” with the project.

The acting is indeed uniformly fine, and though the dubbing is better than average, the voices have that slightly disembodied quality. The dynamic Adamczyk gives a luminous performance, portraying Karol with vigor and grace, and is immensely sympathetic. And his faith and moral rectitude are most convincingly portrayed.

Bela, Bova, Craven and Shopov all contribute excellent performances.

Though this is a lavish production with great crowd scenes and religious ceremonies reverently recreated, director Giacomo Battiato’s use of close-ups of the good-looking cast’s expressive faces keeps you glued to the human drama.

Occasional lapses into sentimentality notwithstanding, the narrative is well-told and absorbing. Even with its undoubted dramatic license and telescoping of events, you’ll readily succumb to the compelling story of a man whose steadfast courage and ideals—particularly his idea of love as the paramount virtue—never wavered even in the face of the evil and hysteria around him.

While not shortchanging the spiritual side of Karol’s life, Battiato and Carmelo Pennisi have cleverly crafted their script with enough elements of wartime thriller and cloak-and-dagger espionage to capture the attention of even those who simply enjoy a gripping survival story.

The film contains wartime violence, including firing-squad executions, and scenes of dead and wounded, partial prison nudity, some unsavory verbal imagery, some crude language and brutal beatings, and as such is best for older adolescents and up.