Christopher was born with cerebral palsy. His father had been deployed to Afghanistan but managed to make it home in time for his birth. After his mother left him, he was mostly raised by his paternal grandparents in El Paso while Eddie took on various jobs to earn a living.
When Eddie gets a job at the Los Angeles Fire Department, Christopher moves with him to Los Angeles to start a new life. Due to his father's long hours, he is also looked after by his paternal great-grandmother Isabel and great-aunt Josephina. Eddie later hires a home nurse Carla to help out.
In the episode "Stuck", Isabel broke her hip and Eddie is forced to bring Christopher to the firehouse. The 118, especially Buck, quickly become fond of him.