Main cast •
Elizabeth Mitchell as Erica Evans: an FBI counterterrorism agent who becomes the leader of the global Fifth Column. Erica seems to become closer to the Visitor Lisa than to her son, Tyler. •
Morris Chestnut as Ryan Nichols: a Visitor posing as human and a Fifth Columnist trying to undermine the insidious plans of the Visitors. He is later forced to betray the Fifth Column due to Anna holding his baby daughter hostage. He is strangled to death by his daughter while trying to remove her from the Visitor mothership in the season-two finale. •
Joel Gretsch as Father Jack Landry: a Catholic priest and former U.S. Army chaplain with two tours in Iraq, whose unease with the Visitors is soon validated by his alliance with Erica over their discovery of the Visitors' secret. Over time, he finds his views of the Visitors conflict with the church hierarchy. He is eventually
laicized after speaking out against the Visitors one time too many, following numerous warnings from the Visitor-controlled Vatican. •
Logan Huffman as Tyler Evans: Erica's teenage son who becomes a V "peace ambassador" and Lisa's love interest. He becomes closer to Anna over time, and at odds with his own mother. The Visitors stripped him of half of his DNA when he was in Erica's womb, which led to his father believing that Erica had an affair. He is killed by Lisa's "twin" sister after mating with her in the season-two finale. •
Lourdes Benedicto as Valerie Stevens (season 1): Ryan's fiancée, who was originally unaware of his alien nature. Her discovery of his secret leads to her being murdered by Anna after giving birth to Ryan's baby. •
Laura Vandervoort as Lisa: a Visitor and Tyler's love interest, who is revealed to be Anna's daughter and next in line to be the Visitors' queen. She displays growing human emotion throughout the first season and joins the Fifth Column in the season finale. Lisa is shown to be closer to Erica than to her own mother; she often confides in Erica about her emotions, and Erica comforts her. In the second-season finale, she is imprisoned by Anna and replaced by her sister, who is identical in appearance (also played by Laura Vandervoort). •
Charles Mesure as Kyle Hobbes (recurring season 1, starring season 2): a former British
SAS soldier and current mercenary, on top of the wanted lists of many law-enforcement organizations who the Fifth Column recruits. The Visitors are revealed to have someone close to him and are blackmailing him. •
Morena Baccarin as Anna: the cold, diabolically manipulative Visitor queen and high commander. She maintains loyalty and control over her subjects by use of a telepathic pacification process known as "Bliss". •
Scott Wolf as Chad Decker: a television news anchor who becomes the Visitors' spokesperson. He is caught between his journalistic ethics and his ambition when his exclusive access to Anna comes with a price. He turns Fifth Column when he learns the sinister truth about the Visitors, though this remains hidden from Anna until the season-two finale.
Supporting cast •
Christopher Shyer as Marcus: Anna's second-in-command in charge of operations. He is shot in the second season during the Concordia announcements, but has since recovered. •
Mark Hildreth as Joshua: the physician in charge of the medical crew on board the Visitors' New York mothership. In season one, he appears loyal to Anna, but is, in fact, a Fifth Columnist undermining the Visitors' operations from within. After being killed and revived, he awakens in season two with a wiped memory and renewed loyalty to Anna. At the end of season two, he remembers being in Fifth Column after seeing Lisa snoop around on the mothership, and rejoins the network against Anna. •
David Richmond-Peck as Georgie Sutton (season 1): one of the original members of the human resistance who wants revenge against the Visitors for causing his family's deaths after he discovered the V's agenda. In an attempt to save Ryan, he is captured by the Visitors. He is tortured for information and later chooses to die rather than reveal Fifth Column members. •
Roark Critchlow as Paul Kendrick: Erica's superior in the FBI counterterrorism unit. He has long suspected that Erica might be a member of the Fifth Column, and reveals himself to be part of another underground anti-V organization known as Project Aries. •
Alan Tudyk as Dale Maddox (season 1): Erica's first partner in the series. Erica discovers he is a Visitor and wounds him. He ends up on Anna's ship, where he is killed by Joshua, the V physician, who is also a spy for the Fifth Column. • Lucas Wolf, as Samuel (season 1): a Visitor Fifth Columnist who worked alongside Joshua. •
Rekha Sharma as Agent Sarita Malik: an FBI agent assigned to work with Erica. Like Erica's previous partner, she is also revealed to be a V mole. After her true identity is discovered, she is tortured and killed by the Resistance. •
Scott Hylands as Father Travis: an elder priest at the same church where Father Jack works. He appears to side with the Visitors in several conversations with Father Jack. •
Lexa Doig as Dr. Leah Pearlman (season 1): a V doctor posing as Valerie's human physician. She is also Fifth Column. •
Nicholas Lea as Joe Evans: Erica's ex-husband who left her after blood tests revealed that their son, Tyler, could not possibly be his. He tries to reconnect with his wife and son after learning the truth about Tyler's altered DNA. In season two, he is caught in a crossfire between FBI agents and the Fifth Column, and is shot and killed. •
Jane Badler as Diana (season 2): Anna's mother, who is being held prisoner on the Visitor mothership in a secret prison cell made to resemble their home world. This Diana is a completely different character from the one that Badler played in the original 1980s series. She was once Queen until she proposed that the Visitors live in peace with humans. Anna finally overthrew her and imprisoned her for 15 years. She was eventually rescued in the season-two finale, but rather than escape, she chose to confront her subjects and was killed by Anna. •
Bret Harrison, as Sidney Miller (season 2): an evolutionary biologist, whom Erica tracks down to explain the Red Sky. Since then, he has continued to work with the Fifth Column. •
Oded Fehr as Eli Cohn (season 2): an ex-
Mossad agent and the leader of a radical Fifth Column cell, with whom Erica shockingly has a mysterious past. He is killed in a staged hostage crisis after turning over his global contacts, as well as leadership of his cell, to Erica. Rosenbaum has stated, "The two of them have something in common that she [Erica] never would have guessed." •
Jay Karnes as Chris Bolling (season 2): Erica's newly assigned FBI partner, who trained with her at
Quantico. He begins to suspect that Erica may have divided loyalties when it comes to her dedication to bringing down the Fifth Column. In the season-two finale, he is revealed to be a member of a secret global anti-V cabal known as Project Aries. •
Martin Cummins as Thomas (season 2): the chief engineer of Anna's Concordia project who is temporarily promoted to second-in-command following the shooting of Marcus. •
Ona Grauer as Kerry Eltoff (season 2): Chad's co-anchor on
Prime Focus, added by their producer to provide an opposing viewpoint to Chad's Visitor-centric reporting. He tricks her into claiming that sources showed a citywide blackout was the result of the unstable Visitor Concordia generator, causing her to be fired for false reporting. Anna had revealed to Chad, though, that Kerry's viewpoints were "dangerous" to Visitor/human relations and would not be tolerated. So, in getting her fired, Chad not only removed her as a threat to his cover but also protected her from Anna's wrath. •
Marc Singer as Lars Tremont (season 2): a member of a top-secret organization of high-ranking military and government leaders (called Project Aries), who know more about the Visitors than most, and have been secretly preparing for a Visitor attack. Singer also played a leading role in the original 1980s series. == Production ==