Babies aren't born Maniacs: this one came to be when his parents died a tragic death, leaving him to be raised by his freezing cold aunt and uncle. Jeffrey becomes Maniac when he takes off running. He starts out just running away from Uncle Dan and Aunt Dot, but by the time he reaches Two Mills, it's clear he's not just running away: he's also running toward. This sets us up for Maniac's ongoing attempt to find a place to call home.
After a pit stop in a zoo, Maniac finds a home with the Beales on 728 Sycamore. Inside 728, life is hunky dory. He's a same-age sibling to his buddy Amanda, cool older bro to Hester and Lester, faithful walk/run companion to Bow Wow, and loving son to Mr. And Mrs. B. In return, the Beales shower Maniac with the family love and affection he's been missing.
But it isn't easy being the only white guy East of Hector. Just when things really couldn't get any better, a tirade from a grumpy old man, some graffiti and an act of vandalism all combine to make Maniac believe he cannot stay with the Beales anymore. So, he does what he does whenever he's faced with a problem: he runs. (Maybe we should call this "running" action.)
Maniac's living in the park again, but this time in the baseball supply room, and he's got a family in Grayson. Until Grayson dies. Wait, what? Yeah, we had to read that part a couple times too. Grayson is really dead, and Maniac is really alone. Again. And it's just a few days after a truly awesome Christmas. This is basically the worst things can get, so we know it's the climax.
He's basically willing to give up and join Grayson in the hereafter when a couple of scruffy ragamuffins interrupt his plans. Foiling Piper and Russell McNab's ill-conceived Mexican vacation plans provides just the reason Maniac needs to keep trying. And so he heads back to Two Mills.
Maniac moves back to Two Mills with Russell and Piper, but all is not groovy. Turns out that Russell and Piper have a bro, and his name starts with Big. Big John McNab that is. And there's an even bigger, scarier, drunker McNab lurking: Papa McNab. This is not a happy, or sanitary place to live. Maniac stays anyway, partly out of a sense of duty to Russell and Piper (someone's got to make sure they go to school, right?) and at least partly because he's not sure where else to go.
Things get bad with the McNabs, and Maniac (you guessed it) takes off. But he sticks around Two Mills, and pretty soon he's got a new bud: Mars Bar himself. Their growing relationship helps lead Maniac back where he belongs: with the Beales. Maybe Maniac isn't the only one who's colorblind.