Eugene Hamilton is the (sometimes friendly) enemy of Johnny and Dukey, preferring to go by name of "Bling-Bling Boy" (because of his gold jewelry and watches). He is a multi-millionaire with unlimited funds at his disposal.
He has a big crush on Susan, who doesn't reciprocate his feelings, and often resorts to evil plots or blackmail to try and force her to be his girlfriend. He occasionally teams up with Johnny and Dukey to defeat the other villains when the situation demands it. He seems to be good friends with Johnny and Dukey, despite being the main antagonist of the series.
Similar to his sisters, he occasionally tricks Johnny into testing some of his inventions. Deep down Bling-Bling Boy is insecure due to being fat and having buck teeth although in Phat Johnny his weight and buck teeth actually help Bling-Bling Boy become successful as a hip hop star. He has a mother who punishes him for "embarrassing her" by plotting his evil schemes. He used to also attend the Mega Institution of Technology, but left the school after his thesis ate Professor Slopsink's hand. He later was allowed to return to the Institute in exchange for aiding in preventing a nuclear crisis, finally admitting to missing human interaction.
In "Johnny X Strikes Back" he had the power of gold vision and flight. In "Johnny's 100th episode", he bawled after thinking that Johnny was dead, but was glad he was still alive (even though he was an enemy to him).
- He is about 4'9 and 180 lbs.
- Most characters usually call him by his real name instead of Bling-Bling Boy, which annoys him greatly.