In the early 1930s was a fairly young truck driver working in the upper midwest. He met a young Teamsters union organizer named Jimmy Hoffa. Despite the risk to his job he eventually agreed to let Hoffa ride in his cab, and listened to Hoffa as he encouraged Ciaro to join the Teamsters. A few days later Hoffa showed up at Bobby's workplace and accidentally got him fired. Bobby tried to seek revenge but was convinced at gunpoint to back away by Hoffa's partner Billy Flynn.
Flynn and Hoffa needed a driver for a job, namely to blow up a laundry that was not cooperate with Hoffa's unionization efforts and hired Bobby for the job. The two men blew up the laundry but Flynn was fatally burned in the process. At the hospital Bobby backed up Hoffa when the police questioned them. Hoffa and Bobby watched as Flynn was given last rights and died. Bobby quickly took Flynn's place as his right hand man.
Being of Italian heritage Bobby was fluent in Italian - this came in very handy when Hoffa was brought to meet with the Mafia. At this meeting Hoffa convinced the Mafia to join his cause, beginning a 40 year alliance.
As Hoffa gained power and experience Bobby remained at his side, hitching his star to Hoffa's. Enjoying hunting he accompanied Hoffa on a hunting trip, during which Hoffa and his Mafia ally Carlo "Dally" D'Allesandro set up a pension fund for the Teamsters that the Mafia was able to use to launder money.
Hoffa was coming to the attention of very highly placed people in the United States Government. In particular he came to the attention of a young Robert Kennedy, who made it his mission to end the corruption of the mafia in organized labor. Hoffa would tangle with Kennedy for the remainder of his life. As the government closed in around on Hoffa Ciaro pressed his staff not to cooperate with the government. Very aggressive with government agents he came across, he refused to give any information on Hoffa.
Ciaro was a thug. He once sent male reproductive organs to a newspaper reporter who was doing stories on Hoffa, intimidating the reporter into killing the story. He started telling people that when Flynn died he told the priest off when given the chance to give a final confession (which might not have been true).
Bobby was eventually convicted of several serious crimes, along with Hoffa. The two men were sent to prison in Pennsylvania. Many of the guards and the others in prison considered Hoffa to be a friend and the guards tried to make life as comfortable as possible for Hoffa and Bobby.
Bobby was released shortly before Hoffa. Meeting with Dally on how to get Hoffa out of prison Dally suggested having the Teamsters endorse Nixon, who would in turn get Hoffa out of prison. This succeeded but there was a price - the government required Hoffa to stay out of organized labor for ten years. Hoffa blamed his former ally Fitz for what happened. Bobby helped Hoffa as he began a campaign against Fitz, which resulted in the death of a driver when someone wired Fitz's car to explode.
Dally confronted Bobby over Hoffa's actions. Bobby told Dally that Jimmy was about to go to the media if he couldn't get back in charge of the Teamsters, Dally decided Jimmy had to be dealt with.
Jimmy and Bobby were asked to meet Dally at the Machus Red Fox Diner in a rural area near Detroit. Delaying them for several hours a hit man arrived in guise of a trucker with a broken down truck. When this hitman confirmed Hoffa was sitting in a car near the restaurant this hit man shot Jimmy Hoffa several times, killing him. Bobby was also killed and his body put in the car with Hoffa's corpse. The car they were in was put in the back of a semi, which drove off into the Michigan countryside.
- Bobby Ciaro was played by Danny DeVito, who also played the Penguin in Batman Returns, Harry Wormwood in Matilda, and Mr. Swackhammer in Space Jam. In addition to playing Ciaro DeVito also directed the film.
- The character of Bobby Ciaro was an amalgamation of several different Hoffa associates over Hoffa's career in the Teamsters.