1980: Sean Cudahy adored his big brother, Tom Cudahy, and wanted to be just like him. The only difference was that the con-man had never done an honest days work. Using Tom’s good name, Sean got a job with Palmer Cortlandt.
Sean tested the limits in Pine Valley. He began an affair with a very married Devon McFadden, all the while dating nurse Sybil Thorne. He enjoyed seducing the much younger and innocent Devon, but the game grew boring quickly. He eventually became the boy-toy of a much older Daisy Cortlandt, who he believed to be a woman named Monique Jonvil.
Palmer wanted Sean to keep an eye on his daughter, Nina Cortlandt, so that he would know her whereabouts. One day, Sean, Nina and Tom’s newest girlfriend Brooke English were trapped in a bank during a robbery. Nina fell into a diabetic coma. Sean took control of the situation, and was looked upon as hero by everyone in Pine Valley.

1981: Sean found cancelled checks in Palmer’s account made out to Daisy Cortlandt. He knew this could not be possible, as Daisy died after Nina's childbirth. He shared his suspicions with Monique, who assured him that it could not be possible.
Sean played an integral role in Palmer’s plot to break up Nina's marriage to Cliff Warner. But his partner in crime, Sybil, was getting cold feet. Palmer sent Sean to her apartment with a gun to scare her into complying. But Sean freaked out and accidentally pulled the trigger.
Cliff went to trial for Sybil’s murderer. Sean thought he was in the clear until Monique turned on him. Not only did she know Sean had seen Sybil that night, she was also the long thought dead Daisy Cortlandt. In prison, Sean admitted to the crime but pleaded for leniency. He was convicted of murder and sentenced to three to five years in prison.

1988: A seemingly reformed Sean Cudahy was released early from prison because of good behavior. He proved that he had reformed to Tom by telling him about his current wife, Skye Cudahy’s, plans to harm Barbara Montgomery.
But, life in Pine Valley made it easy for Sean to slip back into his old ways. He met rich heiress Cecily Davidson. Cecily became smitten with the much older Sean. He proposed marriage to her, knowing it would give her early access to her trust fund. But, Cecily’s mother, Bitsy Davidson, had other plans. She wanted Sean for herself, and began her own seduction.

1989-91: On Sean’s wedding day to Cecily, Bitsy made one last move on Sean. Cecily caught them in a passionate embrace. She left him standing at the altar.
Without the big pay out from Cecily, Sean turned to Palmer for work. Palmer wanted Sean to seduce Opal Gardner, who was in love with Palmer. Sean obliged, but recognized that the attraction was not mutual.
Palmer offered Sean a job with Cortlandt Electronics out of Pine Valley.