Sarah Carter attended Georgetown with Jake, seemingly unaware that the entire four years they went to school together, Jake had been carrying a torch for her. When they meet again years later, she's working as a Congressional Aide investigating DOD funds which were diverted to the NSA for the nanotechnology research. At first unable to look beyond Jake's geeky exterior, his new-found confidence prompts her to wonder if there might be more to Jake than she had previously assumed. However, after a disastrous first date, she bid Jake farewell.
Kevin Flynn (DuMont) is a hacker whom Jake and Kyle busted after he stole $2 million from the Federal Reserve Bank. DuMont attended Carnegie Mellon for undergrad, Cal Tech for his masters, has a Doctorate from MIT and did his doctoral thesis on heuristic algorithms. DuMont is a fantasy geek, spending hours online playing multi-player fantasy RPGS, and named his cell phone Fionnbhair, his mp-3 Earthsea, his PDA Gondor, his hard drive Gormenghast, and his password was Death Owl. Jake posed as DuMont, and brought down a ring of hackers intent on crashing a plane belonging to DuMont's former employers, Banatech, which would have killed everyone on-board. Dumont planned the job with McP, however Yori, Bit and Clu believed they were simply going to hold the jet for ransom. DuMont and Yori were having "cyber sex" for six months, but had never met face-to-face. DuMont is now being held in a Federal prison.
Darin Metcalf was Jake's roommate and co-worker. Darin used to pick up chicks using his NSA badge, pretending to be a spy. Darin was transferred "out of the country" after Jake was infected with the nanites.
Fran Yoshida is Diane's research assistant. She covered with Lou for Diane when Diane followed Jake to Seattle, and also helped Diane monitor Jake using the JMD when Jake lost his memory. In addition to being Diane's assistant, she is also Diane's friend, even when this means taking the heat from Lou and Kyle.
Chief Director Skerrit is Lou's immediate superior and mentor.
Executive Director Valerie Warner is Skerrit's immediate superior. Warner has taken significant interest in the nanite project, and Jake; an interest that worries the team. Unbeknownst to Lou, Warner has met several times with DuMont since he was recaptured.
Tech Agent Susan Carver works under Kyle in Sat Ops. Occasionally snarky, she is almost a fifth member of the team, and is always there day or night.
Tech Agent Hart works under Kyle in Sat Ops.
Seymour Lafortunata works out of the basement of the NSA. One of the NSA's best HUMINT resources, Seymour knows everyone. Literally.
Karen is Jake's neighbour, and seems unusually curious about Jake's life.
Kevin Park is one of Jake's best friends from college. Jake was Kevin's best man when Kevin got married. The wedding was held in Seattle, presumably where they live and work.
Jenny Park was a friend of both Jake and Sarah Carter from Georgetown. Jake was best man at her wedding to husband Kevin. She digs geeks.
Jerry Foley is Jake's 19 year old brother. Jerry currently attends junior college, and always has some scam going.
Dr. Gage was the head of the NSA's nanotech project, and Diane's boss for three years, until he was killed while trying to transmit his research to IRA arms dealer Eric Vaughn. Gage was a jerk who believed "Equal Opportunity" was something you put in your coffee.
Rachel (Yori) is a hacker recruited by DuMont and McP. Her speciality was telecommunications, and she and DuMont had been "doing it" online for six months. When jake was revealed to be impersonating DuMont, Yori helped save the Banatech plane.
Richard "Dick" Fox is a legendary NSA operative with a few secrets. Fox was plagued by mental problems, causing him to create a second personality, "Dick", to deal with the reality of being obsolete in the post-Cold War era, a well as the stress of his work during the 1970s and 1980s at the NSA. He is now on medication and seeing professional help to handle his problems, and is a friend to Jake.
Theresa Carano is the daughter of dangerous arms dealer Ruben Carano. When her father was killed in a plane crash, Theresa covered up his death and took over the family business. When the NSA discovered her "father" was smuggling micro-semtex into the country to sell to terrorists, she seduced Jake in an attempt to throw the NSA off the trail. However, she slipped up, and Jake discovered her true identity and captured her.
Steve Clemens was a Cryptologist working at the NSA. He was hired by the Russian Mafia to help Vasily Koronkiewicz kidnap Diane. Steve seduced Diane--who had no idea she was a target--and murdered Vasily to cover his tracks.
Angela Hamilton is an ex-CIA operative who stole three vials of varcon gas (a biological weapon the United States has never officially created, let alone sold) and tried to murder Colonel Enrique Alonzo, head of the Santa Costa revolutionary guard, in revenge for the death of her younger sister. Angela seduced Jake, then roped him into helping her. Jake felt compassion for her plight, and blackmailed the NSA into getting her released from a Santa Costan prison.
Miles Jennings sat on the Board of Inquiry which almost shut the nanite project down, following the Varcon gas incident. Jennings is highly critical of the project, and in particular, Jake. He was also disgusted by Warner and Skerrit allowing the team to blackmail the NSA and said as much to Warner, who threatened to cut out his tongue.
Wong Mei Ling is a double-agent with whom Kyle had a tempestuous romantic relationship. Two years prior, they had planned to run away together, however Kyle learned that his cover had been compromised and in order to protect her stood her up. Believing Kyle had betrayed her, she sold him out to the Chinese government. Upon learning the truth, she helped him escape.
General Wesley Freewald was a former member of the Wolf Pack, a black-ops team based out of Ft. McLelland. Lou Beckett served under Freewald during the Gulf War and the two shared a healthy respect for one another. When Freewald was murdered by the Pack, Lou personally led the mission to bring his killers to justice.
Vanessa Cardounel is DuMont's girlfriend, and posed as Jake's "wife" in DuMont's scheme to get revenge on Jake and acquire the nanites. Vanessa injected herself with the nanites, and disappeared.
Alex Brandt was a demolitions expert with whom Lou had a clandestine affair which ended when she took the job as Director of Field Operations. Brandt married a woman named Jennifer, but remained a member of Lou's team until he was presumed dead while on a mission to Serbia. After spending 5 years in a POW camp, Brandt was rescued, and attempted to kill Lou because she left him behind. Lou was unharmed, but Brandt did kill Agent Ben Wilton by mistake. Alex was smart, and funny, but not very nice.