Eugene "Bling-Bling Boy" Hamilton Sr (voiced by Lee Tockar) is the rival/anti-hero of Johnny and Dukey. He prefers to go by the title of his self given nickname because of his gold jewelry and watches. Most characters usually call him by his real name instead of Bling-Bling Boy, which annoys him greatly, though in Season 5, he doesn't get annoyed anymore; this is probably because he's realized that nobody will ever call him "Bling-Bling Boy Sr" and has so settled for being known as Eugene Sr.
He is a multi-millionaire with unlimited funds at his disposal. He has a big crush on Susan who does not 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, since he sees a lot of himself in Johnny. He has a mother who punishes him for embarrassing her by plotting his evil schemes. So she grabs him by the ear and drags him. 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 and finally admitting to missing human interaction. In Johnny X Strikes Back he gains the power of gold vision and flight when he helped Super Dukey, Susan, Mary, Bumper, and Gil rescue Johnny X from the Johnny Stopping Evil Force 5.
- His female counterpart is Glam-Glam Girl. She was only seen in Johnny Alternative.
- In Johnny vs. Bling-Bling 3, the only time Bling-Bling Boy stopped liking Susan was when he ate an anti-Susan love pill. Unfortunately, this backfires as he instead, falls in love with Mary. But it was mentioned by Susan that the pill will wear off about 30 days and Bling Bling will fall for Susan again.
- He had a green "BB" in season 1.