Quinn claims to have been a candidate for the first Intersect before CIA Agent Bryce Larkin stole it and sent it to Chuck on "Chuck Versus the Intersect". As a result of this, Nicholas failed his mission and was held captive by his enemies for over a year. He was later discharged from the CIA despite being the best. Since then, he formed a freelance spy firm and has served Fulcrum, The Ring and Volkoff Industries as his clients, all of which were thwarted by Chuck with his aid of the Intersect. In turn, Quinn seeks to steal the Intersect 2.0 from Carmichael Industries during "Chuck Versus Bo".
In "Chuck Versus Bo", it is revealed that during Morgan's time as the Intersect and he yelled his mouth off that he was, Quinn sent an agent, Bo Derek, to seduce and capture him. Quinn revealed himself to be in possession of Intersect glasses, before attempting to gas Morgan with X-13 short-term memory gas. However, just as he was sprayed, Morgan zoomed and escaped with the glasses.
A few months later, Team Bartowski began retracing Morgan's lost memories and discovered the glasses hidden in a game display at the Buy More in Vail, Colorado. Quinn figured it out too and confronted the team. Though Chuck attempts to reason that the Intersect has been nothing but trouble, Quinn retorted that he got a wife out of it. Casey starts a firefight before Quinn escaped, though Chuck chose not to pursue him. This proved to be a mistake, as Quinn captured Chuck and tried ransoming him for the glasses.
In"Chuck Versus the Bullet Train", Quinn manages to kidnap an Intersect-driven Sarah by tranquilizing her when she chased him, while Team Bartowski was still catching up to them. Having studied the Intersect for years, he is aware that Sarah and Morgan's version of the Intersect 2.0 can be corrupted from excessive use. Quinn uses this knowledge to lobotomize her, convincing her that she is still a CIA agent and that he is her handler. He twists her even further when he claims that Chuck was responsible for sabotaging a CIA mission on the Bullet Train. He used Sarah to try and steal the Intersect, as well as kill Chuck. Once he had the Intersect glasses in his hands, Quinn confessed to Sarah that he lied to her. He then moved to shoot her, only for Chuck to take the bullet, though he survived because he was wearing a vest.
Though he finally had what he wanted, Quinn couldn't take the chance that the Intersect may be faulty like that last ones. To that end, he pursued The Key, a device designed to alter the Intersect's original function and perfect. The Key was split between its lead designers, Stephen Bartowski, Ted Roark and Hartley Winterbottom.
Quinn first met with a Fulcrum agent onboard an airplane. But as soon as he got the first piece, Sarah attempted to ambush him but lost her balance. She then was then forced to jump out the door.
The second piece was in the possession of a Ring agent in Germany. Quinn changed the meeting place a few times, inadvertently bringing Sarah through the events of her first meeting with Chuck. At a Wienerlicious, Quinn finally arrived and shot the Ring agent and took his piece. His men also took Morgan hostage, as his spy van was easy to spot. Sarah is able to get the drop on him as she throws some wooden sticks, forcing him to retreat. He gets away after Chuck hesitates to shoot Quinn and unintentionally shoots down Casey's helicopter.
The last Key piece was in the possession of General Beckman. While she was attending a concert with her Chinese counterpart, Quinn hid a bomb beneath her chair set to go off once the musics ends, as he takes the final piece.
With the Intersect perfected and his extraction incoming, Quinn assumed that he was set for life. He was then cornered by Chuck and Sarah, who try convincing him to disarm his bomb. Quinn refused to help and expected to hear an explosion, only to hear Jeffster! singing a-ha's Take On Me. Unwilling to lose, Quinn goes for his gun, only for Sarah to shoot him dead. Chuck is then forced to take the Intersect to save Beckman.
- Professionalism - Quinn's professionalism as a spy is portrayed in Chuck vs Bo, when he wipes out Morgan's memories after getting the answers he needed about the Intersect.
- Manipulation - Quinn is very good at using his words, expressions and tone to convince the subject that he is telling the truth. This is witnessed when he shows up at Sarah's house right after wiping her memories clean, and then convinces her that he is her CIA handler.
- Combat - Quinn's obsession with the Intersect led to him studying the program thoroughly and mimicking it, making him a really skilled combatant in pretty much any fighting style, almost like a human Intersect without the actual Intersect.
- Leadership - As the owner of his freelance spy agency, he seems to be very successful, which is indicative of the presence of strong leadership. He is also shown to be very efficient in the field along with subordinate agents.
- Planning - Quinn is shown to be a meticulous planner. After his interrogation with Morgan, he wipes out the latter's memories with the X-13 gas. After Sarah finishes her mission to capture Chuck, Casey and Morgan in the Intersect room and download the Intersect onto the glasses, he is revealed to have his own detonator button with him, whilst it was earlier believed that Sarah was the only one who had it. In the last episode, he is shown to have set up a sonic bomb in the Orchestra hall to keep General Beckman fully cooperative, and has an extraction team incoming not much later on.
Quinn is described as obsessive. He blames all his failures on not having received the Intersect in the first place, as well as Chuck for being the recipient. Thus, he was willing to do everything and anything to get what he believes he deserves.
While he doesn't seem to care about harming innocent people, as witnessed when he detonates the Intersect room at the CIA facility, he is not particularly maniacal and motivated to keep doing that. At Chuck and Sarah's dream home, he reveals to Sarah that he had been lying to her all along once he had the Intersect glasses, indicating that he only harms innocent people only as long as it's necessary for him to get what he wants.
Quinn is also a very dedicated agent, as he still went out in the field during his CIA days, even though he didn't get the Intersect upload he was about to. And his dedication is much more immensely portrayed when he tells Chuck how he had obsessively studied every version of the Intersect, which is quite a difficult task.
Anna Wu • Alex McHugh • Alexei Volkoff • Bryce Larkin • Carina Miller • Clara Woodcomb • Clyde Decker • Daniel Shaw • Diane Beckman • Emmett Milbarge • Gertrude Verbanski • Hannah • Harry Tang • Jane Bentley • Jill Roberts • Langston Graham • Mary Bartowski • Nicholas Quinn • Stephen Bartowski • Vivian Volkoff