Newton "Newt" Neutron is Jimmy's uncle and a seemingly, mild-mannered, semi middle-aged man who is Eddie's father. He only appears in Clash of the Cousins. He has voiced by Mark DeCarlo.
Newt, like Jimmy's other relatives, he hates Jimmy for nearly destroying the town, most noticeably when he said: Or those evil rotten aliens. He has black-brown hair and more than likely reconciled with Jimmy after discovering it was Baby Eddie who tried to kill him and the others. Newt was very shocked to witness the true intelligence of his son when he spoke in front of the family.
Newt Neutron is taller than his wife Kari and has dressed much more casually than her. He wears a black collared shirt with sleeves that he rolls up above the elbow. His shirt has tucked into a pair of worn blue jeans held up by a brown belt. His work boots are also brown and are mostly covers by his pant legs.
He has dark brown eyes and dark brown wavy hair that reaches the mid of his back. He wears his hair in a ponytail through the back of his baseball cap. His baseball cap is dark brown with a dark green decal on the top and a dark green underside.
He has a unibrow that dips down in the center and is thicker at the ends. He has a round nose of average size. His facial hair is thick on the sides, and his mustache is attached to his beard. His eyes are a dark shade of brown.
- He is modeled after Keith Alcorn.
- He has a striking appearance to John A. Davis, the show's creator.