From left to right:Andrew Duggan as Murdoch Lancer.
Wayne Maunder as Scott Lancer.
Elizabeth Baur as Teresa O'Brien.
James Stacy as Johnny (Madrid) Lancer.
Paul Brinegar as Jellifer (Jelly) B. Hoskins.
Murdoch Lancer is an immigrant from Scotland, who married a wealthy Bostonian's daughter one year after arriving in the United States from Inverness and then moved to California to build a ranch. Two years after Catherine died--apparently giving birth to their son, Scott, who was taken east by her father--Murdoch meets and marries a Mexican girl, named Maria, in Matamoras. A couple of years later, she takes their son, Johnny, and runs off with a gambler. Murdoch is separated from both sons until a few months after he and his foreman, Paul O'Brien, are ambushed by Day Pardee in Morro Coyo while attempting to recover a stolen horse in November of 1869.
Scott Lancer is Murdoch's only son by first wife, Catherine. Raised by his maternal grandfather, Harlan Garrett, who refused to give him up when Murdoch came for him on his 5th birthday, Scott has no contact with his father, knows nothing of having a brother, and attends Harvard at some unknown point in time. He also becomes a Lieutenant in the Union Cavalry and spends a year in a Confederate prison camp during the Civil War. When he is approximately 24 years old, he is contacted by an agent of the Pinkerton Detective Agency, which was hired by Murdoch Lancer to offer his sons an all-expenses-paid trip to California plus $1,000 for one hour of their time.
Johnny (Madrid) Lancer is Murdoch's son by second wife, Maria. Taken from Lancer by his mother when he was less than two years old, he grows up in Mexico and spends time playing around in border towns. Sometime between his 10th and 16th birthdays (the timing is ambiguous in the episodes), he kills his first man and goes on to become Johnny Madrid, an expensive gun for hire. A few seconds before he is to be executed by a firing squad in Mexico, a Pinkerton agent finds him, buys his freedom, and tells him that his father wants to see him and is willing to pay him $1000 for his time. After saving both himself and the agent from the Mexican officials, who change their mind after taking payment for his release, Johnny heads for California, where he finds that not only does he have a father who wanted him, but he also has a half brother.
Teresa O'Brien, a girl in her mid-teens, is Murdoch's ward and believed to be orphaned daughter of Paul O'Brien, Murdoch's friend and foreman for sixteen years. (A later episode reveals that her mother is still living.) She was raised at the Lancer ranch, and is treated like a daughter by Murdoch and like a sister by his sons.
Jellifer (Jelly) Hoskins joins the cast of characters halfway through the first season. After Murdoch bails him out of some trouble, which involved the taking of money stolen by bank robbers, stealing food from the Lancers, and taking Teresa's pearls in order to care for the orphaned boys in his charge, Jelly becomes a trusted employee and friend of the Lancers.