The title of caporegime (capo) has been in existence since the days of pioneering organized crime figures such as Giuseppe "Joe The Boss" Masseria, and Lucky Luciano. However, it was made popular by The Godfather and would go on to be used in several other productions about the American mafia, including Goodfellas and The Sopranos.
In the highly celebrated Corleone tale, several capos work under Vito and Michael. Some are brilliant, establishing themselves as some of the best characters in gangster movie history. Others rub fans the wrong way, specifically because they make poor decisions and keep working against some of the fan-favorite characters.
Frank Pentangeli
Facing charges of bookmaking, drug possession, and first-degree murder, Pentangeli chose to become an FBI informant, a sin considered the worst in the Cosa Nostra. Unable to kill him before the Senate hearings, Michael brought in his brother Vincenzo to the hearings as a message. If he talked, Vincenzo would be dead. Afraid, Pentangeli refused to cooperate any further.
Apart from being a Judas, Pentangeli had numerous other negative traits. He enjoyed engaging in disputes a bit too much, as seen from how he kept pushing the Rosato Brothers. He was also overwhelmed by greed, as he looked to keep all the New York territories for himself even though there had been a power-sharing agreement. He was irrational too, insisting on whacking the Rosato Brothers, even when Michael wanted to spare them in order to preserve the deal with Hyman Roth.
Tessio
Tessio was described as one of the smartest gangsters in the New York underworld. He was there from the beginning, starting out with Vito and Clemenza as street hoodlums. He would then become one of the Corleone crime family's first two capos before choosing to betray Michael so that he would take over as boss.
Tessio's reputation as a master planner made him a bit more likable than Pentangeli. His plan to get Michael whacked at Don Emilio Barzini's Peace Summit in Brooklyn was well-thought-out and he also deserved credit for the formation, as he was a major player in the Olive Oil War. However, his decision to plot against the boss out of lust for power made him an eternal villain in the eyes of fans.
Willie Cici
A former employee of the Genco Pura Olive Oil Company, Cicci squeezed himself and conducted a number of hits before being promoted to capo. His most memorable act was shooting Don Carmine Cuneo as he got a haircut at the same time that Michael Rizzi's baptism was taking place.
While Cicci's quick rise to the top deserved applause, he destroyed the good image he had created for himself by testifying against Michael Corleone at the Senate. His narration of how Michael killed Sollozzo and McCluskey was an act of survival since he had been threatened with life behind bars. Unfortunately for him, it was all in vain since there was no one else to corroborate his testimony. Like everyone else, Pentangeli had been threatened.
Anthony "The Ant" Squigliaro
Squigliaro's cold heart earned him all kinds of animal labels. Apart from being known as "The Ant," he was also referred to as Joey Zasa's "bulldog." The caporegime had a reputation for dipping his bullets in cans of cyanide before using them.
Squigliaro's over-the-top methods were frowned upon by a few, but to most fans, he was a cool character despite his evil actions. Like spy work, organized crime also requires stealth, and Squigliaro established himself as a capable enforcer by disguising himself as an ordinary citizen whenever he was going after foes. There was no major character development for him, but his time in the trilogy could be described as short and sweet.
Rocco
Never one to miss, Rocco was given the task of assassinating major mob players such as Don Tattaglia and Herman Roth. In one of the best kills in The Godfather Trilogy, Rocco famously murdered the traitor Paulie Gatto while Clemenza was urinating just meters away.
Being part of some of the best action scenes in the trilogy made Rocco a standout character. His execution skills helped the Corleone family get rid of the troublesome foes, creating peace that made it easier to conduct business. Rocco getting gunned down by federal agents at Miami International Airport is arguably one of the best death scenes in gangster movies too.
Fausto "Nick" Geraci
After Tessio was exposed and killed for his treachery, Geraci took over as the new capo. He was totally anti-Michael since he felt the young man was unworthy of being boss, however, he was too good a character not to love. Too good that he even wrote a book titled Fausto's Bargain before his death.
It was wise of Geraci to not show his disdain for Michael publicly, even when Michael almost killed him when he tampered with the plane carrying San Francisco and Los Angeles bosses, Anthony Molinari and Frank Falcone. Geraci was also the only hunted man to remain at large for years. To escape Michael's claws, he employed a variety of tactics, such as changing locations, orchestrating a detailed smear campaign against the Don in Sicily, and conspiring with other bosses to vote him out in The Commission.
Richard "Ritchie Two Guns" Nobilio
Richard's cool nickname came when he was "making his bones." His first gun refused to work, so he frantically searched the house looking for another before executing his target. He was also described as one of the best earners in the family. When Michael became Don, he promoted Richard to Capo.
Richard's great sense of humor made him adored by all members of the family. So good were his jokes that other mobsters became uncomfortably whenever he was around their wives. His preference for loud clothing, such as cowboy boots and aviator glasses, communicated to everyone that he was a gangster but he was cautious enough to also be one of the few mobsters in the trilogy who never got killed or arrested.
Sonny
The first among the Corleone siblings was very interested in his father's business from an early age. He got promoted to capo quickly and was being touted as the future boss before being sprayed with bullets in one of the saddest scenes in The Godfather Trilogy.
Nepotism was common in organized crime, but Sonny's meteoric rise to the level of caporegime didn't feel underserved. He proved himself by taking over various territories previously governed by other gangs in New York City. Even more impressive was Sonny's love for family, and anyone who offended a young Connie or Michael was left bloody, bruised, or dead.
Albert "Al" Neri
Al started off as a lawman before diving deep into organized crime. He would go on to be a hitman for the Corleone family before being promoted to capo in the Manhattan faction. Al is best remembered for carrying out high-profile hits, such as that of the corrupt Archbishop Gilday inside the Vatican grounds.
Al was not only effective on the streets but behind closed doors too. The ease at which he manipulated Senator Pat Geary and Meyer Kingsman enable the family to set base in Nevada quickly. Unfortunately, Al's brutality dissuaded any fan from lionizing him, and the manner in which he murdered a sex worker is still disturbing to this day.
Clemenza
The first capo of the Corleone crime family was also the best in every single way. He had multiple iconic scenes, including when he had the turncoat Pualie executed before taking the cannoli and when he trained Michael Corleone for the important task of whacking Captain McCluskey and narcotics dealer Virgil "The Turk" Sollozzo.
Clemenza was the most "likable" capo because he was also the most loyal to his boss. He protected the family's interests in all ways, even if it meant killing people he was close to. He also had the typical mob fashion sense, dressing in long coats and fedora hats. In addition, the capo was quite the comedian. In fact, some of Clemenza's best quotes have been referenced in other gangster movies.