This movie started the wave of biopics that began after WWII. Larry Parks doesn't look the least bit like Al Jolson. For that matter, the script doesn't look much like Jolson's life either. However, the film is very entertaining with a few ironies for the classic film buff. When Parks is on stage, you really get a taste of Jolson in his prime. Al Jolson actually tutored Parks in how to move and interact with the audience using his own style, and it comes across well, even if it is obvious that you are hearing Jolson's voice during the performances and that this voice does not match Larry Parks' speaking voice at all.
Jolson's life story has been sanitized here to keep in line with the values of the post-war motion picture production code, right down to extending the life of Jolson's mother an extra forty years - she died when Al was ten. Also, the movie has Jolson playing the career-absorbed bachelor until he meets his wife Julie Benson (code for Ruby Keeler) when he is in his forties. Yes, Al was career-absorbed, but he still went through two marriages and two divorces before he ever got to Ruby Keeler.
Two very interesting points of the film involve the insertion of the fictional character Steve Martin that allegedly got Al into show business and also the choice of director. The first interesting point is that fictional character Steve Martin is played by William Demarest, who actually had a bit part in 1927's "The Jazz Singer". You'll see him sharing a plate of eggs with Al at Coffee Dan's just minutes before Al bursts into song in "Toot Toot Tootsie". Demarest was a bit player over at Warner's during the beginning of his career. He had no real association with Al Jolson that I know of. The second interesting point is the choice of director - Alfred E. Green. Mr. Green was among that group of directors that ground out the early talkies for Warner Bros during the time that Jolson was a star at that studio. However, he never directed any of the eight motion pictures that Al Jolson starred in for Warners. There were four directors that Jolson worked with over at Warner Brothers that were still alive when this film was made, but for some reason none of them got the job.
At any rate, the movie is very entertaining and well-paced with great renditions of Jolson's acts and songs. For the unvarnished truth about Jolson's life, try to find a copy of the documentary "The Real Al Jolson Story" made in 1986 and originally telecast by Bravo, back when they really were dedicated to the performing arts and before they became so concerned with Top Chefs and Flipping Out - you know, the same kind of stuff you can find on 50 other channels.