Cally was a waitress at a hotel in Hayleyville, Arkansas, whom J.R. met while on a hunting trip with his brother, Bobby. J.R. seduced Cally into bed, but when J.R. is discovered by her crazed brothers, he is arrested and convicted for rape. After Cally's brothers break J.R. out of prison, Cally lies that she is pregnant, so her brothers force J.R. into a shotgun wedding. J.R. eventually escapes from Hayleyville and returns to Dallas, but Cally shortly thereafter follows him with the intention of making their marriage work. To her dismay, she finds that J.R. wants nothing to do with her.
Seeking the help of J.R.'s first wife, Sue Ellen, Cally tricks J.R. into renewing their wedding vows when she claims she really is pregnant. After tying the knot, J.R. discovers her ruse, but decides to remain married to Cally — mainly because his son John Ross has become fond of his stepmother.
However, their rocky marriage is short-lived as J.R. soon returns to his philandering ways. By the time Cally divorces J.R., she really is pregnant with his child. However, in an attempt to escape from J.R., Cally lies that J.R.'s son James Richard Beaumont, is the child's father and J.R. allows Cally to leave Dallas. Later, upon discovering the child's true paternity, J.R. decides to track Cally down and finds she has created a new life for herself in Florida with her new child. Realizing how happy Cally is, J.R. decides to leave her in peace.
In the very last episode, JR dreams of what life would have been like without him. In the dream Cally is the victim of repeated spousal abuse from a very aggressive husband until she shoots him. In the dream Cally is set to spend life in jail.