The classic photograph that serves as the opening shot of "Living Proof" is one of the most telling moments in the two-hour NBC film about Hank Williams Jr. There's Hank Sr., looming larger than life over his 2-year-old son, who is cradling a miniature ukulele and looking up with awe. There is no shadow in that picture, but there certainly has been in Hank Jr.'s life and that drama is at the heart of "Living Proof" (tonight on Channel 4 at 9).

Junior had it more difficult than most celebrity children because he inherited not only the name but the role. His mother, Audrey, had pushed the father into stardom and after his death (of a heart condition aggravated by alcohol and drug abuse), she pushed the son into the long shadow of the legend. At 8, he became the reincarnation of a man he had never really known (Williams had died when Junior was 3). Despite the age, the imitation was hauntingly uncanny, right down to the gestures, vocal inflections and the lonesome quality that had allowed Hank Williams to reach so many people. "I had the greatest country singer that ever lived and he died untimely," Audrey tells her son early on. "And now I got you."

Junior, played here by Richard Thomas, bore the burden no better than did his father--in some ways, they were both troubled by the same fame. Dwarfed by a giant picture of his father, he debuted at 14 both at the Grand Ole Opry and on "The Ed Sullivan Show"; at 16, he sang his father while George Hamilton acted his father in the film bio "Your Cheatin' Heart." And in a bizarre ploy, Audrey had him recording duets with his long-dead father: "You just try to keep level with your daddy," she advises in the studio. "Don't try to overpower him." It's recording talk, but it's also a prediction.

Audrey could still snarl "You're not your daddy" when it was convenient, but by the time Junior was in his late teens, he was proving her wrong. There were de'ja vu bouts with alcohol, drugs, wild women and wilder marriages, suicide attempts and divorces. Then, just as the son was finally stepping out from the father's shadow by writing his own fine songs and developing a successful progressive country career, Junior suffered a near-fatal fall from Ajax Mountain in Montana. It broke every bone in his face and required extensive rebuilding and rehabilition; the whole sequence has been grittily re-created. Eventually, Junior exorcized his father's demons, settled into a happy marriage and (in terms of record sales and chart success) eclipsed his father. He's now one of the biggest stars in country music.

All in all, it's a compelling tale, and director Dick Lowry has done a remarkable job of compressing 30 years into 120 minutes. Thanks to beautifully crisp photography and editing, a sound track that's willing to drop the music for significant dramatic stretches, and a dozen small but accurate touches, Lowry has managed to capture the often debilitating requirements of a life in music, particularly the coldness of buses, backstages and motel living (the last via a remarkably accurate slow-motion party sequence).

Thomas may be a bit too milquetoasty for the role of Hank Jr., but that's probably just the Walton in him; as matters get worse, he gets better. But Lowry should have let Hank Jr. do all the vocals (he does seven out of 11) because Thomas' voice simply doesn't have the needed weight. Ironically, there's not enough of the kind of songs Junior used to free himself of Senior (the powerful song that gives the show and the autobiographical book it's based on its name is in the throwaway line, "that sucker casts a long shadow, I'm the living proof of that"). If some of the telescoping of events is awkward, then the payoff at the end, with Junior as a Good Ole Superstar, is a bit too quick. "Living Proof" is one of the few TV-bios that could have used another 30 minutes.

The supporting cast is generally good, particularly songwriter/road manager Merle Kilgoe as himself, Ann Gillespie as Junior's second wife (she's unimpressed at their first meeting: "If you were me, would you go out with you?") and the sensual Liane Langland as the first wife who turns out to be a lot like his mother, a sort of Audrey Jr. The realistic screenplay, by Stephen Kandel and I.C. Rapoport, benefits from the writers' feel for country dialogue ("I know I've been a mean patient." "You haven't been mean. You just haven't been patient."). It shows that everybody did some listening to the music; they end up putting in as much as they got out of it.