Battlestar Galactica

William Adama (Edward James Olmos)

 A former Viper pilot in the Colonial Fleet during the First Cylon War, now the commander of the aged Battlestar Galactica with his old friend, Saul Tigh, as his executive officer. His eldest son died in a flight accident, and his second son, Lee "Apollo" Adama, is an accomplished Viper pilot. When the Cylons attack the Twelve Colonies, he is, as commander of the only functioning Battlestar, charged with defending the Colonies' remaining survivors.

Laura Roslin (Mary McDonnell)

 The former Secretary of Education of the Twelve Colonies, appointed President when all of the officials above her in the line of succession are killed in the Cylon attack on the Colonies. Just before the attack, she was diagnosed with breast cancer and told she had only one year left to live. She and Adama uneasily share responsibility for leading the fleet of survivors, and they often clash due to their differing backgrounds and perspectives.

Kara "Starbuck" Thrace (Katee Sackhoff)

 A highly irreverent Viper pilot serving on the Battlestar Galactica. She was engaged to William Adama's oldest son, Zak Adama, at the time of his death, having been his flight instructor during his Viper training. Adama cares for her deeply, seeing her as a surrogate daughter, although she has many flaws. She is also the Galactica's top Viper pilot, although her irascible nature often puts her in conflict with her superiors, most notably X.O. Tigh.

Lee "Apollo" Adama (Jamie Bamber)

 William Adama's second son and a skilled Viper pilot in his own right. He blamed his brother's death on his father, and he stopped speaking to him and Starbuck for two years. By a twist of fate, he is on the Battlestar Galactica as a guest for its decommissioning when the Cylons attack the Colonies, and when the ship's senior Viper pilot is killed in action, he is placed in charge of the Galactica's pilots.

Dr. Gaius Baltar (James Callis)

 An egotistical, neurotic, womanizing, sarcastic scientist who developed a computer navigation system utilized by most military ships and many civilian ships. He is responsible for giving the Cylons access to this system, having been unknowingly seduced by one of the human models, Number Six. He manages to secure a spot on a Raptor to flee the Colonies because of his intelligence and fame, and once in the refugee fleet, he tries to conceal his complicity in the attack.

Number Six (Tricia Helfer)

 The sixth model of humanoid Cylons. She is exceptionally beautiful, and her platinum blonde hair tends to make her stand out in a crowd. The most notable Number Six was assigned to seduce Dr. Gaius Baltar in order to gain access to the Twelve Colonies' ship navigation and defensive systems, allowing the Cylon forces to destroy the Colonies with ease. When the Cylons attack, this Six sacrifices herself to shield Baltar from an explosion.

Number Eight (Grace Park)

 The eighth model of humanoid Cylons. One of the Number Eights was a sleeper agent who infiltrated the Colonial military as the Raptor pilot, Sharon "Boomer" Valerii, who believes she was from a mining colony. She is romantically involved with the Battlestar Galactica's Viper and Raptor maintenance and damage control chief, Galen Tyrol. She and Karl "Helo" Agathon crash-land on Caprica when the Cylons attack, and she transports Dr. Gaius Baltar to the Galactica via Raptor.

Saul Tigh (Michael Hogan)

 The executive officer of the Battlestar Galactica and an old friend of William Adama who has worked with him for years. He is divorced from his wife, Ellen Tigh, as she committed numerous infidelities while he was in space. He is an extremely irritable man with strong proclivities toward heavy drinking. He has a particularly antagonistic relationship with Viper pilot Kara "Starbuck" Thrace.

Karl "Helo" Agathon (Tahmoh Penikett)

 Sharon "Boomer" Valerii's Raptor partner and an old academy friend and drinking partner of Kara "Starbuck" Thrace. When he and Sharon crash-land on Caprica during the Cylon attack, he gives up his seat on the Raptor to allow Dr. Gaius Baltar to escape and tries to evade the Cylons in the wilderness. He is a man of strong opinions and great personal integrity.

Galen Tyrol (Aaron Douglas)

 The Battlestar Galactica's Viper and Raptor maintenance and damage control chief. He has served in the Colonial Fleet for eighteen years on four different Battlestars. He is romantically involved with Sharon "Boomer" Valerii; although he is initially unaware that she is a Cylon, he takes note of her increasingly odd behavior. He is loyal and fiercely protective of the people under his command.

Felix Gaeta (Alessandro Juliani)

 The Battlestar Galactica's tactical officer. He has great respect for William Adama, under whom he has served for the past three years. He is very friendly, trusting, and idealistic, though the Cylon attack on the Twelve Colonies has shaken him as much as everyone else. He is also very intelligent, having studied genetics in college, and considers Dr. Gaius Baltar his personal hero.

Samuel T. Anders (Michael Trucco)

 One of the star players for the Caprica Buccaneers, a team for the Twelve Colonies popular sport called Pyramid. He and his team survive the Cylon attack on the Twelve Colonies because they are off in the wilderness training. They become a resistance cell, fighting against the Cylons whenever they can, with Anders acting as their de facto leader.

Anastasia Dualla (Kandyse McClure)

 The Battlestar Galactica's chief communications officer, responsible for intra-refugee fleet communications and Galactica-to-Viper/Raptor communications. She also helps coordinate the fleet's FTL jumps. During the Cylon attack on the Twelve Colonies, she monitors communications traffic and hears some reports of the attack. She and President Laura Roslin's aide, Billy Keikeya, are mutually attracted. She is a very dutiful and dedicated officer.

Callandra Henderson (Nicki Clyne)

 An air maintenance specialist working under Galen Tyrol on the Battlestar Galactica, better known by her nickname, "Cally." She has a crush on Tyrol, though she helps cover for him when he is off spending time with Sharon "Boomer" Valerii. Her small size makes it easier for her to get into small compartments in Vipers and Raptors to repair them.

Billy Keikeya (Paul Campbell)

A young political official assigned to be Secretary of Education Laura Roslin's aide for the Battlestar Galactica's decommissioning, just before the Cylon attack on the Twelve Colonies. When Roslin becomes president, he assists her with the difficult task of managing the civilians' day­-to-day concerns. He and Roslin are fiercely loyal to each other, and he is attracted to Communications Officer Anastasia Dualla.