Tom Hagen is the main character in The Godfather novel and the first and second films.
Tom was the son of Martin and Bridget Hagen, and was of Irish-German ancestry. Martin was an alcoholic who abandoned Tom after Bridget died. Tom was homeless when he was discovered by Sonny Corleone, who brought him home and convinced his father Vito Corleone to take him in.
Vito did not adopt Hagen because he thought it would be extremely disrespectful to Tom's parents, but he became every bit the father Tom never had. Tom went to law school and became a lawyer. After graduating from law school Tom entered into the family business.
When Vito's orginal consigliere Genco Abbandando became seriously ill Vito made Tom acting consigliere. Upon Abbandando's death Vito named Tom consigliere on a permanent basis, which was controversial due to Tom's non-Italian heritage.
After the assassination attempt on Vito Tom was kidnapped by Virgil Sollozzo and asked to help Sonny see reason regarding the drug trade. Tom said he would try but not even Sonny would be able to call off Luca Brasi, not knowing that Luca was already dead. Sollozzo told Tom to let him worry about Luca.
Upon being released Tom made his way to the Corleone compound where he met with Sonny, the capos Peter Clemenza and Salvatore Tessio, and Michael Corleone to determine the next moves. Michael left for the hospital to visit his father and was able to save Vito's life when assassins tried to kill him in his hospital bed. When Captain McClusky of the NYPD arrived he broke Michael's jaw when Michael asked him why the men guarding his father were taken away. Tom arrived with private detectives who went up to guard Vito's room and warned McClusky that if he tried to interfere he would have to go before a judge in the morning and show cause as to why they should be removed.
At a meeting following the hospital incident Michael suggested killing both Sollozzo and Captain McClusky. Sonny mocked Michael, thinking he was taking it very personally. Additionally there was the old prohibition against killing police officers. Michael argued that since McClusky was working for Sollozzo he lost that protection. He suggested that journalists on the Corleone payroll would like a story of a corrupt police officer taken down by his mafia allies and that it would soften the public's perception of the Corleone family. Tom agreed with him that they probably would.
Michael was able to kill both Sollozzo and McClusky in an Italian restaurant in the Bronx. He then fled to Sicily to avoid criminal charges and the retaliation of the other crime families. Michael's girlfriend Kay tried to reach him and brought a letter for him to the Corleone compound. Tom refused to accept it since it would be admissible in court that he had knowledge of where Michael was hiding.
During the war between the families Tom tried to counsel Sonny to make peace, Sonny refused on the grounds that it was showing weakness and berated Tom for not being a wartime consigliere as Genco had been. When Sonny was killed in an ambush, it was Tom who broke the news to Vito that his son was dead. Vito ordered no investigation and no acts of reprisal for Sonny's death. He further asked Tom to call the heads of the Five Families and arrange a meeting of the Commission. Tom accompanied Vito to the mortuary where Vito called in his favor with the mortician and asked him to do all he could to make Sonny presentable to his mother for his funeral.
After Vito's retirement Tom was removed as consigliere by Michael Corleone as Tom was not a wartime consigliere. Following Vito's death Michael reappointed him as consigliere, a role Tom held as Michael made the Corleone family into one of the most powerful crime families in the nation. Their relationship was not without its bumps, when Tom questioned Michael the Don told him that if he wasn't with him Tom could take his family and his mistress and leave. Tom asked Michael why wounded him and that he was always loyal.
Tom died sometime prior to 1979. His son Andrew was ordained to the priesthood, and due to the recommendation of Michael he was assigned to the Vatican. Michael remembered Tom fondly as a great lawyer.
- Tom Hagen was portrayed in the first and second films by Robert Duvall. Duvall also voiced Hagen in The Godfather video games.
- Tom Hagen was originally going to return for The Godfather Part 3, and the central plot was going to be a split between Tom and Michael. The character was killed off when the film's producers refused to accommodate Duvall's salary demands.
- The supplemental materials included on The Godfather Part 3 DVD stated that Hagen died at some point during the 1970s.
- In The Godfather's Revenge Tom was murdered by Nick Geraci in 1963, who bound him up in a car which he sank in a swamp. Tom's body was never found, but Geraci sent Michael a dead baby alligator with a wallet in his mouth - a message that Tom Hagen now slept with the alligators. This death was considered non-canonical by Paramount as they had not authorized that novel.