The film starts as Timon and Pumbaa are shown watching the opening act of the original film in a dark theater when Timon suddenly uses a remote control to fast forward to where they appear in the film. Pumbaa argues that the film shouldn't go out of order and attempts to rewind the film back to the beginning. Timon and Pumbaa start fighting over control of the film until they agree that the film should tell their side of the story. Throughout the rest of the film, it's occasionally interrupted to have Timon and Pumbaa comment on whatever is happening. Mystery Science Theater 3000-like moments occur as the characters comment on the original film's proceedings. When the film ends, in a theater, Pumbaa insists on watching it again. Timon protests until all their friends and almost every Disney character come to watch it too (with Pumbaa commenting that he still does not "do so well in crowds").
While the original film, The Lion King, seemed to be based on Hamlet, this film might have been inspired by the Tom Stoppard play Rosencrantz and Guildenstern are Dead, in which the titular characters are seen in every major event of Hamlet.
At Timon’s meerkat colony far away from Pride Rock, Timon takes jobs as a digger and a sentry, but despite his mother Ma's encouragement, he cannot seem to find a good job for himself. After his uncle Max is nearly eaten by Shenzi, Banzai and Ed on his watch, Timon decides to leave the meerkat colony and find a place that is right for him. He is encouraged by a baboon named Rafiki to seek Hakuna Matata and to look beyond what he sees, and has the intuition to head for Pride Rock. Along the way, Timon and Pumbaa meet for the first time and set out to find a "dream home."
The adventures of Timon and Pumbaa begin to coincide with the events of The Lion King at this point. They arrive at Pride Rock, but to their dismay a herd of animals is already there. While Timon and Pumbaa are walking through the herd of animals witnessing the presentation of the newborn prince Simba, Pumbaa accidentally flatlets, which causes a few animals to pass out and collapse. The animals in front see this and believe that the fallen animals are bowing, and soon they all bow together. Simba's father King Mufasa was very puzzled at seeing this, but his majordomo Zazu tells him that they are bowing to Simba.
Timon and Pumbaa continue their journey and find a new home at a watering hole that looks like a miniature version of Pride Rock. One morning, they are disturbed by some noise from outside, which is actually Simba, his friend Nala, and the animals singing "I Just Can't Wait to Be King". Timon is angry and hits the leg of an elephant supporting the tower of animals. The elephant jumps in surprise and causes the tower to collapse, explaining why it collapses in the original film.
Timon and Pumbaa's home is ruined by this event. Pumbaa tells Timon about a "dream home" in the jungle, but Timon ignores him. They travel to the elephant graveyard and witness Mufasa and Zazu saving the cubs from the hyenas. That night, going further into the graveyard, they watch an army of hyenas marching to the instrumental opening of "Be Prepared", and the duo run away. Later, they end up in the gorge only to encounter a wildebeest stampede, the same one from the original film in which Simba loses his father. While trying to run from the wildebeests, they fall down a waterfall, which leads to the "dream home" that Pumbaa had described. The song "Hakuna Matata" has turned into a sing-along. Timon and Pumbaa later find Simba, and the film shows some of their life in the jungle throughout the years.
As a young adult, Simba re-encounters Nala. Afraid of losing their friend, Timon and Pumbaa try everything to stop Simba and Nala from falling in love. Simba and Nala fall off the cliff in the original film when Timon and Pumbaa trip Simba and Nala with a vine. In the original film, Timon and Pumbaa reappear in another place at the end of the "Can You Feel the Love Tonight" sequence because they were running around trying to interfere with the lions during the song. Although they fail, they are happy to see Simba arguing with Nala and running off to the grasslands. They mistake Mufasa's ghost appearing in the clouds as bad weather. In the morning, however, they realize that Simba has returned home to challenge Scar. Pumbaa and Timon disagree about whether to go after Simba, but ultimately both decide to return to Pride Rock.
There, Timon re-encounters Ma and Uncle Max for the first time since he left the colony. Ma and Max make a system of tunnels to trap the hyenas while Timon and Pumbaa create a diversion, from spinning plates, to doing the Can-Can, to breakdancing, and finally, to everybody's amazement, horror and disgust, proposing to Shenzi. This diverts the hyenas long enough for the meerkats to complete and collapse the tunnel trap.
After defeating Scar, Simba becomes the king, avenging Mufasa and Timon tells Ma that he found his place, but something is still missing: his family. In the end, Timon and Pumbaa return to their jungle paradise, bringing Timon's entire meerkat colony with them. The meerkats now have a safe, work-free place to call home, and Timon is hailed a hero.
- The French track on the DVD plays (in English) "Can You Feel the Love Tonight?" during the end credits instead of "Grazing in the Grass" performed by Raven and "That's All I Need Reprise" performed by Timon.
- Outside of the USA the sing-along lyrics are omitted, but there's still a ladybug bouncing on the screen excluding the Arabic version, which has the Arabic lyrics featured with the ladybug bouncing on each word.
- The French track on the DVD plays a cover of Kool and the Gang's "Jungle Boogie" in place of the original. Unless otherwise noted, all other songs featured in the movie are sung in French.
- Nathan Lane as Timon
- Ernie Sabella as Pumbaa
- Julie Kavner as Ma
- Jerry Stiller as Uncle Max
- Matthew Broderick as Simba (teenager and young adult)
- Robert Guillaume as Rafiki
- Moira Kelly as Nala
- Whoopi Goldberg, Cheech Marin and Jim Cummings as Shenzi, Banzai and Ed
- Edward Hibbert as Zazu
- Jason Rudofsky as Flinchy
- Matt Weinberg as Young Simba
- Mickey Mouse
- Snow White and the seven Dwarves in order: Dopey, Bashful, Doc, Sneezy, Happy, Sleepy, and Grumpy from Snow White and the Seven Dwarfs
- Beast, Mrs. Potts, Chip and Belle from Beauty and the Beast
- Lady and Tramp from Lady and the Tramp (Timon and Pumbaa also re-did their famous spaghetti kiss scene during "Hakuna Matata".)
- Hyacinth Hippo from Fantasia
- Genie, Aladdin, Jasmine, and Carpet from Aladdin
- Stitch from Lilo & Stitch
- Mad Hatter from Alice in Wonderland
- Rabbit from The Many Adventures of Winnie the Pooh, often mistaken for the March Hare
- Donald Duck
- Quasimodo, Hugo, Victor, and Laverne from The Hunchback of Notre Dame
- Peter Pan, Tinker Bell, and the Lost Boys from Peter Pan
- Pocahontas from Pocahontas
- Mowgli and Baloo from The Jungle Book
- Terk from Tarzan
- Dumbo from Dumbo
- Flora, Fauna and Merryweather from Sleeping Beauty
- and Br'er Bear from Song of the South
- Jeff Bennett as Bashful
- Tony Anselmo as Donald Duck
- Bill Farmer as Goofy
- Corey Burton as Grumpy
- Kevin Schon as Happy
- Shaun Fleming as Lost Boys
- Blayne Weaver as Peter Pan
- Bill Farmer as Sleepy
- Bob Joles as Sneezy
- Carolyn Gardner as Snow White
- Chris Sanders as Stitch
There's a game on the 2-Disc DVD called "Find the Face", where other Disney characters appear including Sebastian and Ursula (The Little Mermaid), Gus and Cinderella (Cinderella), Bambi (Bambi), Aurora (Sleeping Beauty), Queen of Hearts (Alice in Wonderland), Kronk and Emperor Kuzco (The Emperor's New Groove), Gaston (Beauty and the Beast), Mushu (Mulan), Iago (Aladdin), Ichabod Crane (The Adventures of Ichabod and Mr. Toad), Robin Hood (Robin Hood), Panic and Pegasus (Hercules), Jiminy Cricket and Pinocchio (Pinocchio), and Wart (The Sword in the Stone).
Based on 17 reviews from review aggregator Rotten Tomatoes, the film has a 79% approval rating, with an average rating of 6.4. The film has a more mixed rating of 65% in the RT community, with a score of 3.2/5.
In February 2004, more than 3 million copies of its VHS and DVD units were sold in its first days. In the same month, it was reported the film sold about 2.5 million out of 3.1 million DVD copies before its first weekend generating about $55 million in its first three days of release. A DVD boxed set of the three Lion King films (in two-disc Special Edition formats) was released on December 6, 2004. In January 2005, the film, along with the sequels, went back into moratorium.
The Lion King 1½ was first released on Blu-ray in an eight-disc trilogy box set on October 4, 2011. It received its separate Blu-ray release on March 6, 2012. It was produced in two different packages, a 2-disc version with Blu-ray and DVD, and a DVD version.
The film soundtrack, The Lion King 1½: Songs From Timon and Pumbaa's Hilarious Adventure, was released to CD by Disney Records on February 10, 2004. It includes two songs from the original film, "That's All I Need" and "Hakuna Matata", re-performed by Nathan Lane who took over the role of voicing the character Timon. The rest of the soundtrack includes various R&B tracks, including remakes of the Kool and the Gang classic "Jungle Boogie" by artist French, and two instrumental pieces from composer Don Harper. Ennio Morricone was the original composer of "The Good, The Bad, and the Ugly".
- "Grazing In The Grass" (Raven-Symoné)
- "Digga Tunnah Dance" (Lebo M and Vinx)
- "That's All I Need" (Nathan Lane) (based on unused song from original film called "Warthog Rhapsody")
- "Hakuna Matata" (Nathan Lane, and Ernie Sabella)
- "The Lion Sleeps Tonight" (Lebo M)
- "Jungle Boogie"
- "Timon's Traveling Theme"
- "The Good, the Bad and the Ugly"
The following awards were won or. Nominated in order:
- 2005 Annie Award for
- "Best Home Entertainment Production" (Won)
- "Music in an Animated Feature Production" (Nominated)
- 2005 DVD Exclusive Awards:
- Best Animated Character Performance (Nathan Lane [voice] and Alexis Stadermann [animator]) for "Timon" (Won)
- Best Animated DVD Premiere Movie (Won)
- Best Director (of a DVD Premiere Movie) - Bradley Raymond (Won)
- Best Editing (of a DVD Premiere Movie) - Joyce Arrastia (Won)
- Best Screenplay (for a DVD Premiere Movie) - Tom Rogers (Won)
- 2005 Saturn Award
- "Best DVD Release" (Nominated)
- Main article: The Lion King 1½ (video game)