|Behind the scenes|
When the Ingalls family moved to Walnut Grove, Charles was looking for extra work; and after seeing the condition of the warehouse's roof he offered to fix it. O'Neil agreed under one condition; if the roof was not fixed in three weeks he would take Charles' oxen as collateral. Charles was injured and in result Doctor Baker warned him not to work.
Charles still attempted to do the job, but realized how injured he was; Mary and Laura tried to finish the work, which was soon noticed by the townspeople of Walnut Grove and the menfolk finished the job for the Ingalls.
He is not seen after this event, but it can be assumed that as he seemed ashamed of his actions he would of probably left Walnut Grove.
Behind the scenes
Liam O'Neil was portrayed by Ramon Bieri.