Theo Hoffman arrived in Port Charles in 2010 wanting revenge against Brenda Barrett for the death of his son, Aleksander Janáček. When Theo first arrived in Port Charles he posed as a patient at General Hospital that was suffering from a severe illness, but tests proved that nothing was wrong with Theo physically. He insisted that something was wrong and conflicted with several doctors on the General Hospital staff. He even went as far as to sue the hospital for incompetent service. His desire for what he deemed as competent service put him in contact with Dr. Robin Scorpio-Drake and he quickly befriended her because he saw her as a competent doctor. Eventually he was diagnosed with a psychological condition called hypochondria by Robin and satisfied with the correct diagnosis he decided to drop the law suit against the hospital.
After ending the ruse with the hospital, he goes to Diane Miller wanting to join her law firm Mason, Petrovich, and Miller. He was hired and soon given a wrongful death lawsuit that had been filed against Brenda and Dante Falconeri. He used his position as Brenda's attorney to get closer to her and exact his revenge. Theo had been behind the whole entire lawsuit and it was just a part of his plan for revenge. Brenda dated Aleksander in the past but after finding out his connections with the mob and trafficking she left him and fled to New York where Dante became her bodyguard.
Brenda and Dante were not aware of their mutual connection to Sonny at the time and while in New York, Brenda found out that she was pregnant. Aleksander became obsessed with Brenda and followed her to New York. After stalking her, he ended up in a confrontation with Dante and he shot and killed Aleksander. He then covered up the crime by dumping Aleksander's body in a swamp and telling Brenda that no one would ever find out what happened.
Theo wanted Brenda to pay for Aleksander's death. He finally made his move on Brenda's wedding day to Sonny Corinthos and everyone found out that Theo was really the international criminal named The Balkan. After the wedding he had a bomb planted in Sonny and Brenda's limo. He then kidnapped and drugged Sam Morgan due to her resemblance to Brenda and put her in the limo. Brenda got into the limo and right before it exploded she was taken out of the limo and kidnapped. Sonny was devastated thinking that Brenda had died in the same way that his first wife Lily had. When the body was recovered from the car they found that it had been Sam in the limo and not Brenda, devastating Jason, but luckily due to the bomb-proofing in the limo, Sam survived and was taken to the hospital. Jason went with Sam to the hospital and Sonny turned his attention to finding Brenda. Theo took Brenda to a cave compound and demanded to know the whereabouts of his grandson. Brenda believed that she had a miscarriage in her seventh month of pregnancy and told him so, but Theo would not believe her.
During this time it was also revealed that Suzanne Stanwyck, Brenda's long time friend and the director of her charity, the Alliance to Save Exploited Children was really Theo's wife and just as eager to avenge her son Aleksander's death as Theo was. Her whole plan for getting close to Brenda had been for revenge and to get her hands on her grandson because she knew that Brenda had been pregnant and that her son was still alive. What Brenda had thought to be a miscarriage due to a fever, had really been Suzanne drugging her so that she could induce her labor early and take the baby. After interrogating Brenda in the cave, Theo learned that Suzanne had known about the pregnancy and interrogated her. However Suzanne explained to Theo that she didn't want to add anymore sorrow to him after losing Aleksander and Theo seemed partially satisfied with the answer, until he learned that Suzanne had been with Brenda during her pregnancy and he became convinced that Suzanne had taken the baby away so that Theo would never know him.
Search for Alec and death
Sonny, Jason, and Dante manage to track Theo down to the cave compound and they rescue Brenda. Theo uses Suzanne as a human shield and manages to get away while Jason and Dante chase after him. Sonny rushes Brenda to a hospital because when Theo learned that Sonny was close to finding them, he injected Brenda with a deadly neuro-toxin intended to kill her before making his escape. Thanks to the efforts of Dr. Patrick Drake, a successful antidote was made and Brenda recovered. Theo then turned his attention to finding his grandson and in the process tried to kill Suzanne but due to her connections with some of his men she survived. Later, Theo had gotten closer to his grandson's location. He found him, but before he could meet his grandson, Suzanne killed Theo by slitting his throat.
Numerous unknown crimes during his years as an international crime lord known as "The Balkan" [pre-2010-2011; revealed on Dec 17, 2010]
Sent his minions to disfigure, drug, torture, and kidnap Brenda Barrett [Summer 2010; revealed on Dec 17, 2010]
Arranged to have Jerry killed by having a hitman shoot him with a Polonium-210 laced bullet after Jerry failed to bring Aleksander home [Dec 20, 2010; Jerry was revealed to be alive on Aug 3, 2012; Jerry was revealed to have Polonium-210 on Sep 11, 2012]