Balto was the final animated feature produced by Steven Spielberg's Amblimation animation studio. Although the film's theatrical run was overshadowed by the success of the competing Pixar film, Toy Story, its subsequent strong sales on home video led to two direct-to-video sequels Balto II: Wolf Quest (2000) and Balto III: Wings of Change (2004).
In New York City, an elderly woman, her granddaughter and her Siberian Husky, Blaze, are walking through Central Park, looking for a memorial statue. As they seat themselves for a rest, the grandmother tells a story of the 1925 serum run to Nome.
The story goes back to the winter of 1925 in Nome, Alaska. Balto, a young wolfdog, lives in the outskirts of Nome with his adoptive father, a snow goose named Boris and two polar bears, Muk and Luk. Being half-wolf, Balto is shunned by dogs and humans alike. His only friends in town are a red husky named Jenna whom Balto has a crush on, and her owner, Rosy. He is routinely challenged by the town's favorite sled dog, Steele, a fierce and arrogant Alaskan Malamute with whom he competes for Jenna's attention.
The evening after the annual dog race, 18 children, including Rosy, are taken to a hospital, apparently feeling very ill, which worries Jenna. After confirming the diagnosis, Dr. Curtis Welch informs that Rosy and the other children have been stricken with diphtheria, and he is out of antitoxin. The local wireless operator relays news of the outbreak and word travels to the territory capital of Juneau, where the governor orders a crate of antitoxin to be sent to Nome. However, severe winter weather conditions prevent medicine from being brought by sea or air and the closest rail line from Juneau ends at Nenana, 600 miles east of Nome. A dog race is held to determine the best-fit dogs for a sled dog team to get the medicine. Balto enters and wins, but Steele got him disqualified by stomping on Balto's paw, which inflicts Balto to growl in pain and accidentally bare his wolf teeth in front of the musher, causing the humans to fear that Balto might turn on the musher due to his wolf heritage.
The team departs that night with Steele in the lead and successfully picks up the medicine, but on the way back conditions deteriorate and the disoriented team ends up stranded at the base of a steep mountainside slope with their musher knocked unconscious. When word reaches Nome that the sled team is missing, the town prepares for the worst, and even the town's carpenter Mr. Johansson sadly proceeds to build child-sized coffins for the sick children. Balto sets out in search of the team, marking his trail by clawing trees, along with Boris, Muk, and Luk. On the way, they are ambushed by a giant grizzly bear, but Jenna, who followed their mark tracks, intervenes. The bear pursues Balto out onto a frozen lake, where it falls through the ice and drowns, while Muk and Luk dive in to save Balto from a similar fate. Jenna is injured in the bear fight and cannot continue. Balto instructs Boris and the polar bears to take her back home while he continues on alone; Jenna gives him her bandana and Boris gives him some advice.
Balto eventually finds the team and offers to guide them home, but Steele, only caring about his position and fame, refuses to accept help and repeatedly attacks Balto, only to lose his balance and fall over a cliff. The sled dogs, having seen how insane Steele is, let Balto take charge of the team. Steele, being the ingrate that he is, spitefully camouflages Balto's markings with fake ones, and they are thrown off the trail. As a result, Balto panics and runs too fast, and then he and the medicine fall over a cliff. Back in Nome, Jenna is explaining Balto's mission to the other dogs, but they don't believe her. When Steele returns, he claims the entire team, including Balto, is dead; he uses Jenna's bandana as supposed proof. However, Jenna sees through his lies and insists that Balto is coming home with the medicine, but the other dogs remain skeptical. Using a trick Balto showed her earlier, Jenna places broken colored glass bottles on the boundary of town and shines a lantern on them to simulate an illusion of the Northern Lights, hoping it will help guide Balto home.
Balto regains consciousness believing to have failed miserably, but after a polar wolf (Balto's mother) appears and Balto notices the medicine still intact, he realizes his part-wolf heritage is strength, not a weakness, and drags the medicine back up the cliff to the waiting team. Using his highly developed senses of smell, Balto is able to filter out the false markings Steele created. After overcoming several near-catastrophes, and losing only one vial, Balto and the sled team finally make it back to Nome. A pity-playing Steele is exposed as a liar and as a result, the other dogs angrily abandon Steele, ruining his reputation. Reunited with Jenna, Boris, Muk, and Luk, Balto is hailed the town's hero by both the other dogs and the townspeople. He visits a cured Rosy who thanks him for saving her life.
Back in the present day, the elderly woman, her granddaughter and Blaze finally found Balto's memorial (courtesy of Blaze's smell senses), and she expresses that even today, Alaska runs the Iditarod Trail Sled Dog Race over the same path that Balto and his team took from Nenana to Nome. When the woman's granddaughter asks if Blaze can do exactly what Balto did, the woman says if Blaze practices a lot, it's possible he can. The woman is then revealed to be Rosy when she repeats the same line, "Thank you, Balto, I would've been lost without you," before walking off to join her granddaughter and Blaze. The film ends with Balto's statue standing proudly in the sunlight.
- Kevin Bacon as Balto, a young adult male wolfdog; being half-husky and half-wolf. His biological father was a Siberian husky and his biological mother, Aniu was a wild, white wolf. Jeffrey James Varab and Dick Zondag served as the supervising animators for Balto.
- Bob Hoskins as Boris, a Russian snow goose and Balto's caretaker and sidekick. Kristof Serrand served as the supervising animator for Boris.
- Bridget Fonda as Jenna, a female Husky and Rosie's pet as well as Balto's love interest. Robert Stevenhagen served as the supervising animator for Jenna.
- Juliette Brewer as young Rosy, Jenna's owner and a kind, excitable girl who was the only human in Nome who is kind to Balto. She falls ill, but Balto brings the medicine to save her and the other children. David Bowers served as the supervising animator for Rosie.
- Miriam Margolyes as old Rosie in the live-action sequences who tells her story to her granddaughter.
- Jim Cummings as Steele, an Alaskan Malamute and Balto's rival who also has a crush on Jenna. Sahin Ersöz served as the supervising animator for Steele.
- Phil Collins as Muk and Luk, a pair of polar bear cubs, Muk talks but not Luk. Nicolas Marlet served as the supervising animator for Muk and Luk.
- Jack Angel, Danny Mann and Robbie Rist as Nikki, Kaltag and Star (respectively), the members of Steele's team. William Salazar served as the supervising animator for the team.
- Sandra Dickinson as Dixie, a female Pomeranian and one of Jenna's friends who adores Steele until his lies are exposed. Dickinson also voices Sylvie, a female Afghan Hound who is Jenna's friend as well; and Rosie's mother. Patrick Mate served as the supervising animator for Sylvie and Dixie.
- Lola Bates-Campbell as Rosy's granddaughter, who appears in the live-action sequences and is accompanied by her dog Blaze, purebred Siberian Husky.
- William Roberts as Rosy's father
- Donald Sinden as a doctor
- Bill Bailey as a butcher
- Garrick Hagon as a telegraph operator
- Frank Welker as the Grizzly Bear
“Balto” was the final animated feature produced by Steven Spielberg's Amblimation animation studio before Spielberg co-founded DreamWorks (along with David Geffen & Jeffrey Katzenberg) and most of the Amblimation staff were re-located to DreamWorks Animation.
Originally, Brendan Fraser was hired to provide the voice of Steele and he recorded his part, but his voice-over was subsequently discarded and the role went to Jim Cummings instead.
The movie also marks actress Bridget Fonda's first venture into animated films, in addition to many cast members in the film.
The characters Muk and Luk were named for mukluks which is a type of Canadian footwear. The character design for Jenna was based on actress Audrey Hepburn.
- The film portrays Balto (1919–March 1933) as a gray wolfdog. In real life, Balto was a pure bred Siberian Husky and was black and white in color. Balto's colors changed to brown due to light exposure whilst on display in the Cleveland Museum of Natural History. The filmmakers may have chosen to differentiate Balto from the other prominent sled dog of the movie, Steele, who also had a black and white coat.
- The sled run to retrieve the medicine was a relay. Instead of being the leader of the first team, Balto was the leader of the last team to carry the medicine to Nome. The longest and most hazardous distance was traveled by the team led by Togo.
- The medicine was never driven by the dogs alone and none of the mushers were incapacitated.
- Balto was never an outcast street dog as shown in the movie, but was instead born in a kennel owned by the famous musher Leonhard Seppala, where he was trained until deemed fit for pulling a sled as the lead dog. Seppala was also the owner of Togo (1913–1929), whom he personally used to lead his dog team during the relay. He was used by one of Seppala's workers, Gunnar Kaasen.
- Balto is the only animal and the only character in the movie who is based on an actual historical figure.
- In the sequels, Balto was shown to have offspring, but in real life, he was neutered at a young age.
- In the sequels, Balto continued living in Nome along with his family and friends (the events of the third film happened in 1928), but in real life, Balto and his team were sent to the Brookside Zoo (now the Cleveland Metroparks Zoo) in 1927 where they spent their last years of life.
“Balto” ranked at #15 at the box office, grossing $1,519,755 during its opening weekend with a domestic gross of $11,348,324. Even though the film wasn’t successful at the box office, it fared better in video sales which led to the release of two direct-to-video sequels, but neither of them received strong reception unlike the original film.
The movie received mixed reviews from critics.
On Rotten Tomatoes, it was given a 50% rating based on 24 reviews. According to the site’s critical consensus: "The animation is great, but Balto's details and its plot are so-so.”
Roger Ebert gave “Balto” a positive review, describing it as "a kids' movie, simply told, with lots of excitement and characters you can care about” & also gave the film 3 out of 4 stars.
Peter Stack of the San Francisco Chronicle called it “a plucky dog story -- especially with funny friends -- is always a winning formula for the G-rated crowd.”
However, other critics criticised the movie for its lackluster voice work (particularly from Kevin Bacon) and its storyline.
Walter Addiego of the San Francisco Examiner wrote in his review that the film “takes a genuinely appealing, inspirational story and reduces it to, at best, a passable entertainment that might please younger children” and that “older youngsters, and certainly their parents, will find it dull and drawn out, full of trite characters and situations.”
The Washington Post’s Rita Kempley wrote in her review that the artistry of the movie “dims in comparison to that of Dogs Playing Poker.”
On Metacritic, it calculated an average score of 52/100 based on 10 reviews which indicates "mixed or average reviews”.