Security guards Chuck (Gailard Sartain) and Bobby (Bill Byrge) play a game of Red light/Green light while being night watchmen for Howard County Bank and Trust and are obsessed with elaborate schemes of would-be thieves. They hear a sound coming from a floor polisher that Ernest is trying to turn on for operation - he works as a night custodian at the bank - and dreams that he would be a clerk. He becomes magnetic from a mishap with the floor polisher and makes a disastrous mess. The next day, bank president Oscar Pendlesmythe's assistant, Charlotte Sparrow (Barbara Bush) insists that he clean up his mess. Pendlesmythe wants to terminate Ernest's employment, but Charlotte has a soft heart for misfits and stray dogs, so she argues on his behalf. Ernest takes a bath at home in a tumble dry washing machine and uses a blow dryer with a windtunnel force for his evening dinner with Charlotte in a restaurant. He later receives a jury duty summons and excitedly tells the two watchmen about it. During the trial Dracup Maximum Security Prison convict Rubin Bartlett notices that death row inmate Felix Nash is a dead ringer for Ernest. Rubin's lawyer convinces the jury to tour the prison, where Ernest is abducted by Nash and another inmate named Lyle. Nash schemes to switch places with Ernest. Even though Ernest tries to tell the guards he is not Nash, they refuse to believe him. He also does not know that he has a death sentence which is for Nash.
While having lunch, a guard tells them to stand up and be quiet, when he notices Ernest is making a lot of noise, which almost sends him into the cell. Ernest tries a first attempt to tell one of the prison guards that he is Ernest, not Nash, but the guard calls him "Mr. Funny Man" (which is a mistaken lie) and angrily says that he is not funny and is lying and throws him into the cell right in front of Lyle who pushes him back while the first attempt fails. When he pushes him near the prison bars, he tells a prison guard that he was beaten up (and accidentally slamming the guard's head on the bars). A prison guard tells Ernest that he will be sent to the hole, which makes Ernest realize he is in jail. Bartlett tells him that Nash has assumed his identity and warns him to keep his mouth shut. Ernest makes several unsuccessful escape attempts (endearing himself to Lyle in the process), and is soon sent to the electric chair by the prison warden (Charles Napier).
The electrocution fails, and Ernest is transformed into a type of superhuman, with the ability to shoot lightning bolts from his hands. He successfully escapes the prison by blasting a hole in the main gates. Making his way home, he discovers that his Pee-wee Herman-like décor has been replaced by a slick Lounge Lizard style of decorating. He exclaims, "I've been vandalized - by Elvis!" Meanwhile, Nash is preparing to blast open the bank's vault with a time bomb, with Charlotte and an unconscious Chuck bound nearby. Charlotte begs Nash not to go through with it, and he blurts the truth about being an impostor. Charlotte doesn't believe it until he points out he's done a far better job cleaning the floors than Ernest ever had. Ernest arrives and he and Nash do battle. Ernest gets electrocuted yet again when Nash throws him against an electric cage that the bank had rigged to drop from the ceiling to catch robbers. Now Ernest has become polarized and gained the ability to fly. He uses his super powers to fly through the skylight of the bank with the bomb which leads to a spectacular mid-air explosion. Everyone especially Chuck thinks that Ernest has been killed, until he falls through the skylight and lands on Nash, which leads the warden and the guards to find out Ernest was right all along. Ernest tiredly declares, "I came, I saw, I got blowed up" and then passes out.
- Jim Varney — Ernest P. Worrell, Auntie Nelda, Felix Nash
- Gailard Sartain — Chuck (security guard)
- Bill Byrge — Bobby (security guard)
- Barbara Tyson (credited as Barbara Bush) — Charlotte Sparrow
- Barry Scott — Rubin Bartlett
- Randall "Tex" Cobb — Lyle
- Dan Leegant — Oscar Pendlesmythe
- Charles Napier — Warden Carmichael
- Jackie Welch — Judge
- Daniel Butler — Waiter at Restaurant
- Emily Corbishdale — Betty McGee
- Andy Stahl — Jerry (as Andrew Stahl)
- Bob Babbitt — Washing Con
- Myke R. Mueller — Vinnie (as Myke Mueller)
- Chambers Stevens — Jury Man (uncredited)
The movie debuted at No.3.
This film's first DVD release was on September 3, 2002 from Walt Disney Studios Home Entertainment. Mill Creek Entertainment re-released it on February 10, 2008 as part of the Ernest 2-Movie Collection with Slam Dunk Ernest and on January 18, 2011 as part of a 2-disc Triple Feature set with Ernest Goes to Camp and Ernest Scared Stupid. They also released the film for the first time on Blu-ray on March 29, 2011 in a single disc Double Feature set along with Ernest Goes to Camp. The 2011 releases mark the first time the film has been available in widescreen.
- ↑ "Weekend Box Office Results for April 6-8, 1990". Box Office Mojo.
- ↑ "Ernest Goes to Jail (1990)". Box Office Mojo.
- ↑ "Review/Film;Ernest Again, Invulnerable To Life's Inanimate Objects", The New York Times.
- ↑ "Ernest Goes to Jail", Deseret News.
- ↑ "Ernest Goes to Jail", Entertainment Weekly.
- ↑ "'Turtles' Take: $50.9 Million in Two Weeks : Box office: The kids movie featuring the wise-cracking quartet of terrapins is close to setting a record for an independent film.", Los Angeles Times.