John and Jenny aren't big into training and by the time they turn to a professional for help Marley's pretty much past the point where he wants to follow any rules. Kicked out of obedience school, Marley continues to misbehave and pretty much control the household.

As Marley grows, so does the Grogan family. Over the years as John and Jenny's brood expands with the addition of three kids, Marley settles into the big brother role – with only occasional streaks of wildness. And as Marley matures into a senior citizen dog the Grogans learn important life lessons from their furry family member.