Harold Finch (Person of Interest)

Harold Finch is a fictional character from the CBS crime drama television series "Person of Interest". He is played by Michael Emerson, and in scenes from his past by Parker Brightman (child) and Chris Bert (teenager). Finch is a reclusive private billionaire software engineer who developed a machine that can isolate the Social Security numbers of people with either premeditated homicidal intent or who will be homicide victims, based on its analysis of surveillance data. He recruits John Reese, a former Green Beret and CIA operative, to help him prevent crimes related to the 'people of interest' that the Machine identifies. He is also known by a series of aliases, many using various bird names as a surname. A quirky and mysterious character, Finch tends to keep his personal life a secret as he rebuffs Reese's numerous attempts to learn more about him.
Background.
Born in Lassiter, Iowa, Harold was raised on a farm by his father; his mother, Margaret Chamberlin, is indicated to have been absent from at least age eight. A child prodigy, he displayed early skills in the fields of mechanical engineering and computer science. With his father suffering early onset dementia, the teenaged Finch grew increasingly interested in artificial intelligence and human-computer interaction. Needing more memory for the machine he was trying to build, Finch hacked into the early military Internet, ARPANET, resulting in his becoming the subject of federal investigation and obliging him to begin living under a false identity. His father had taught him bird names, which might explain his preference for incorporating these into his aliases.
As 'Harold Wren', Finch entered MIT, where he and classmate Nathan Ingram co-founded the computer company 'IFT'. After Finch graduated from MIT he made a deal that Ingram was the public face of the hugely successful business while Harold necessarily remained unseen, accumulating vast wealth without having a public profile. It is made clear in the early seasons that Finch's personal fortune runs into billions of dollars.
After the September 11 attacks, Ingram and Finch began working to create an artificially intelligent machine that could predict terrorist attacks through processing government feeds from emails, phone calls, and surveillance cameras. The machine also generated a list of predicted murders and violent crimes "non-relevant to national security". It was determined that this non-relevant list should have to be ignored, since passing the information to law enforcement agencies could reveal the existence and extent of constitutionally proscribed government surveillance. For this reason, and rationalizing it as done for the greater good, Finch programmed the machine to delete the non-relevant list every day at midnight. Ingram and Finch clashed when Finch discovered that Ingram had created a backdoor into the machine before handing it over and was trying to warn and even save people on the "irrelevant list". Finch shut down the backdoor.
Nathan's moral qualms led him to contact a journalist with the intention of exposing the surveillance program. Anxious to stop him, Finch arrived at their meeting place only in time to see Ingram murdered in a seeming terrorist bombing that as well claimed dozens of innocent lives. Badly injured himself, Finch was taken to the temporary triage. Suspecting (rightly) that the attack was a government sponsored attempt to kill Ingram, and understanding for the first time the lengths to which elements of the government would go to maintain the machine as secret, Finch allowed his fiancée Grace Hendricks to believe he was killed in the bombing. At the secret library location where Ingram had created his backdoor to the machine, Finch reactivated the backdoor and began his own mission to save the non-relevant numbers.
When Finch is arrested in "The Day The World Went Away", it's stated that he's wanted for treason from 1974 and is connected with fifteen open homicides.
Beginning war on crime.
Knowing that he cannot himself intervene, Finch recruits Rick Dillinger, a former Blackwater mercenary. However their relationship is uneasy because of ethical differences. The machine provides Finch and Dillinger the number of Daniel Casey, a computer hacker who tests computer security systems. Dillinger observes that Casey is being pursued by multiple third parties, including Special Control and CIA agents revealed to be John Reese and Kara Stanton. Dillinger rescues Casey and takes him to Finch, who is sympathetic to Casey's predicament. Examining Casey's laptop he concludes that it should be sold to the highest bidder (at some unknown point later in the season two finale, Finch creates and installs onto the laptop a virus to "set the machine free"). Dillinger, who secretly planted a bug to listen in their conversation, decides to go rogue by drugging Finch and stealing the laptop.
Finch follows Dillinger to Central Park and watches from behind a tree as Dillinger gives the laptop to the Chinese buyers. After the trade is made, an unknown assassin (revealed to be Shaw) fires at the buyers at first, prompting them to flee, before shooting Dillinger in the chest. Finch makes his way to Casey and Reese's encounter. Finch watches from behind as Reese lies to Kara, telling her that Casey is dead. Reese tells Casey that he doesn't deserve to die and provides a safe passage in Canada. It is at this point, seeing in Reese the requisite skill-set and a strong sense of moral duty, that Finch begins considering him as replacement for Dillinger.
Activities with John Reese.
When Finch first makes contact with John Reese, Reese is suffering from depression brought on by the death of his former lover and is living on the streets. Defending himself against subway thugs leads Reese to be arrested and questioned by Detective Joss Carter. Finch gets him out of police custody with the help of a costly lawyer and tells him that he needs a purpose and a job, explaining that what he can offer is a "chance to be there in time". After initially refusing, Reese begins on his first case, watching assistant district attorney Diane Hansen.
In the course of this first job Reese blackmails Detective Lionel Fusco to be their informant in the NYPD. When Reese completes the case, Finch tells him, "The numbers never stop coming" (knowing that there will be infinite Social Security numbers and cases to solve, as he agrees to take on the job). As their friendship starts to evolve in the series, Reese becomes increasingly protective of Finch, particularly following Finch's kidnapping by Root. Reese gives Finch his dog Bear as a companion, but also for protection when Reese is not around.
For his part, Reese gives little if any indication that he sees Finch's injuries as a limitation, and has gradually drawn Finch into field work. Although reluctant at first, Finch has increasingly begun to assist Reese in the field, growing in confidence as he does.
After the death of Root, Finch goes on a rogue mission to destroy Samaritan. Guided by the Machine, Finch uploads the Ice-9 virus to Samaritan in ".exe" but it has global side effects. In the series finale "return 0", Reese and Finch work together one last time to destroy a Samaritan copy that uploaded itself to an orbiting satellite. Wounded, Finch attempts to sacrifice himself to upload a copy of the Machine to destroy Samaritan, but is tricked by Reese who sacrifices himself in his place. With Samaritan destroyed and having been reminded of the value of life by the Machine and Reese, Finch returns to his fiancé and a normal life.
Skills.
Throughout the series, Finch displays his extraordinary expertise with computer hacking and advanced technology. As a result of his injury from the ferry bombing, he is unable to fully turn his head, has rigid posture, and walks with a limp. In contrast to Reese, he lacks hand-to-hand combat techniques due to his physical limitations, but he prefers to use self-defense and a non-lethal weapon (such as a Taser when he stunned an NYPD officer inside the morgue in order to help Reese and Carter escape from HR).