Rivet City's hard-nosed security chief, 35-year-old Harkness is a good guy and a good friend, despite his rough demeanor. Harkness is extremely fair-minded. He treats Hangar Deck citizens with the same regard as Upper Deck citizens. As a result, he is very well liked by the Hangar Deck residents.
Harkness is a prototype Generation 3 synthetic humanoid, or "synth," and the most advanced android ever created by the Institute, as of 2277. He originally worked for the Synth Retention Bureau in the Commonwealth. He later escaped after he became sentient and started to sympathize with the escaped synths he was tasked to capture. The synths working at the Synth Retention Bureau are told that those who try to escape are simply malfunctioning, when in actuality their complex AI has allowed them to start thinking for themselves and become fully sentient. The synths that Harkness captured seeded ideas about self-determination and freedom within his mind, thus contributing to his decision to escape. "Self determination is NOT a malfunction," as Harkness would later say in a holotape before escaping.
While he successfully escaped the Commonwealth, he was hunted by the Synth Retention Bureau like any other escapee. He needed to get facial reconstruction surgery, an altered voice, and have his memories of being a synth suppressed/replaced with those of his new Harkness persona. This was all necessary to hinder the SRB's investigation and help him start a new life. With the help of the Railroad, he managed to get in contact with Horace Pinkerton in Rivet City, Capital Wasteland. Pinkerton was one of few surgeons capable of performing the facial surgery, on top of being familiar enough with robotics to be able to suppress/replace Harkness' memories. Pinkerton proceeded to steal a mem chip from Vault 112 and implanted it in A3-21, leading A3-21 to believe himself to be an old combat veteran awakening from a coma.
Upon assuming his new persona, Harkness joined the Rivet City security force, eventually becoming its chief officer and member of the council.
During the day, Harkness will be outside Flak 'N Shrapnel's weapon store in the Rivet City marketplace. He may be on the top floor of the bridge tower from midnight to 6:00 a.m. When meeting him for the first time, if the player character tells him they are going to leave, he'll be stuck at the entrance for the rest of the game. However, the player character can still walk past him without incident.
The Replicated Man: Harkness turns out to be the android which Dr. Zimmer is looking for. The Lone Wanderer can make a choice to either help Harkness to escape notice, or Zimmer, who then takes him back to the Commonwealth.
When first arriving at Rivet City, Harkness will demand the player character to "state their business in Rivet City" before he allows them to enter. No matter what they choose to answer with, he will always allow the player character to enter.
If the player character does not return Harkness to Zimmer, Harkness will stay in Rivet City in a loop, unable to die.
During The Replicated Man quest, after Harkness finds out he is an android and the player character is following him downstairs to the science lab, he can be pickpocketed for the key to the ship's armory.
If the Lone Wanderer allows Zimmer to reclaim Harkness, Zimmer will use a command to restore Harkness to his factory settings. This is referred to as a "recall code" in Fallout 4 and it is explained that every synth has one and the code will activate a hidden subroutine that restores Institute control of the synth in question. This is proven to work even after a memory suppression, which Harkness had done.
If the player character has the Contract Killer perk and kills him using console commands, he will have four ears instead of one.
When prompted with his activation code, Harkness will mention all of the 'runners' he 'brought down.' This is a reference to the movie Blade Runner and the book it was based on, Do Androids Dream of Electric Sheep?. In the movie, Rick Deckard is famous for hunting and eliminating "replicants," which are much like "androids" (or "synths" as they are known in Fallout 4). It is a disputed claim that Deckard himself is a replicant, furthering Harkness's resemblance to him as an artificial being unaware of his synthetic nature that hunts other artificial beings.
One of his replies might be "Oh yeah? And I'm a fairy princess." this is a reference to an utterance made by Max Rockatansky in the film Mad Max Beyond Thunderdome.
PC Should the Lone Wanderer rescue James before reaching Rivet City, Harkness will become stuck at the main entrance. [verified]