Senator Daniel Perrin (portrayed by Alexis Denisof) is a wealthy and powerful US Senator from Virginia who targets the Rossum Corporation (and by extension the Dollhouse) for keeping medical advances secret and conducting illegal human experiments, not knowing he himself is a doll as being used to further Rossum's agenda.
Daniel Perrin came from a family who had a long association with politics, however Daniel himself was a drunken wastrel who had washed out of Yale University and was still partying his life away well into his thirties. This made him the ideal target for Rossum, who were looking to gain a foothold in the US Government. Perrin was captured, and turned into a doll version of himself; he was still Daniel Perrin, but now filled with the drive, ambition and intelligence needed to carve a political career. He was also given a handler by the name of Cindy, who posed as his wife. Perrin had no clue over what had happened to him, and believed himself to be acting under his own free will.
Rising to become a Senator, Perrin was given information about the Dollhouse by a mysterious benefactor, who was actually Rossum himself. His (presumably fictional) backstory involved him losing his mother to Alzheimer's, giving him a personal motivation to go after the Dollhouse since Rossum had technology that could have saved his mother.
Perrin acquires information about Madeline Costley's time with the L.A. Dollhouse, which he shares with her, convincing her to come forward and give testimony to the fact the Dollhouse exists. The L.A. Dollhouse staff assume that Cindy is an Active, used to spy on and control Daniel, and think that Madeline is in danger. While Echo is sent to frame Daniel for adultery, Paul attempts to recover Madeline from Cindy.
Daniel suspects that Echo (imprinted as "Bree") is actually a Doll, and takes her to meet with Cindy. They arrive just as Paul uses the Disruptor, which has no effect on Cindy, but briefly disables both Echo and Daniel.
Cindy uses the Disruptor to capture Echo and Daniel, and ships both of them back to Washington DC Dollhouse. Echo (in doll state) and Daniel escape from the Washington house (part of a plan by Bennett Halverson). They remove each other's tracking device, then run to the empty Perrin compound.
Bennett remotely imprints Daniel with an assassin program to kill Echo, just as Cindy and other Washington agents arrive. While chasing Echo, Perrin kills a guard and Cindy. Topher shuts down the assassin imprint, causing Daniel to be horrified by what he has done.
Daniel arrives at the Senate hearing ready to expose the Dollhouse, however his programming kicks in and instead he clears Rossum of any wrongdoing and instead presents it as having being targeted by a consortium of rival companies who had also killed his wife with a car bomb. Furthermore, he states that the Dollhouse doesn't exist and Madeline as being dangerously delusional having spent three years in a mental institution in Canada.
As a result of this, Rossum was able to not only protect itself from further investigations but now had Perrin able to push through new regulations, allowing the corporation to write laws as it saw fit. They also intended for Perrin to eventually rise through the ranks and become president of the United States (The Left Hand), which he accomplished with him in office during the start of the Apocalypse. (Epitaphs)