Prior to becoming a motivational speaker, Harold Kerwin worked for twelve years as a car salesman and was arrested and charged with two counts of assault for his part in barfights. He served his prison sentence and then went out to the New Mexico desert. After three years, he came back a changed man, alleging that he spent his time meditating and discovering his true "gift". Afterwards, Kerwin, who had changed his name to Barry Flynn at this point, became a motivational speaker who became popular and gained millions of fans around the world, including Carl Finster, a man suffering from synthesthesia, who came to incorporate him into a fantasy world he developed, in which Finster was a superhero killing liars and evildoers and Flynn was his sidekick. When Flynn came to Seattle for a conference, Finster killed two victims to prove his devotion to him. The BAU briefly assumed him as a suspect of the murders.
He first appeared in Magnificent Light, hosting one of his shows. He then gives an excited Cynthia Strobl a backstage tour before quickly dismissing her, having been annoyed by her presence. Flynn then tells his assistant that he will be leaving on one of his mysterious offstage trips, despite there being a number of fans waiting for autographs. He is next sitting at a bar; a man named Ricky Lopez approaches him and offers to be a tour guide, which Flynn accepts. The two leave through another exit of the bar, to which Flynn is ambushed and abducted by Finster, who convinced Lopez to lure him out. Flynn wakes up at Finster's place and meets his abductor, who introduces himself and explains his condition and mission to him. In an effort to survive, Flynn continuously plays along with Finster throughout most of the episode, but bears witness to more of Finster's crimes. He is eventually rescued by the BAU after an attempted attack on an innocent family.
- His story about discovering his true "gift" through meditation in the New Mexico desert is most likely fabricated as presumed by Garcia. However, the subject isn't touched on any further. If this is true, his motivations behind this lie wouldn't be known.
- However, judging by the amount of money that he receives from his conferences, it could be a get-rich-quick scheme. It would also possibly explain why he mysteriously disappears frequently; he presumably spends the acquired money for himself.
- It is implied that Flynn could be homosexual, with Lopez's offer to be a "tour guide" containing the innuendo of a romantic offer.