Young Johnny is gung-ho and full of courage. Johnny's brainiac twin sisters, Susan and Mary, use Johnny as their guinea pig for their outrageous scientific experiments. If they can dream it up, Johnny will do it; as long as his genetically engineered super dog, Dukey, can come along.
2005-09-17 - 2014-06-18
| Title | Name |
|---|---|
| Season 4, Episode 1 | Johnny's New Baby Sisters |
| Season 4, Episode 2 | Porta Johnny |
| Season 4, Episode 3 | Join the Johnny Scouts |
| Season 4, Episode 4 | Johnny BC |
| Season 4, Episode 5 | Runaway Johnny |
| Season 4, Episode 6 | Johnny on the Spot |
| Season 4, Episode 7 | Dark Johnny |
| Season 4, Episode 8 | No Homework for Johnny |
| Season 4, Episode 9 | Papa Johnny |
| Season 4, Episode 10 | The Johnnyminster Dog Show |
| Season 4, Episode 11 | Dukey Jekyll and Johnny Hyde |
| Season 4, Episode 12 | Johnny's Trophy Case |
| Season 4, Episode 13 | Johnny's Amazing Cookie Company |
| Season 4, Episode 14 | Johnny's Big Dumb Sisters |
| Season 4, Episode 15 | My Johnny Guard |
| Season 4, Episode 16 | Tom and Johnny |
| Season 4, Episode 17 | The Quantum of Johnny |
| Season 4, Episode 18 | Johnny Get Yer Gum |
| Season 4, Episode 19 | Old School Johnny |
| Season 4, Episode 20 | Johnny Degrees Below Zero |
| Season 4, Episode 21 | Johnny Johnny |
| Season 4, Episode 22 | Johnny Double Coupons |
| Season 4, Episode 23 | X-Ray Johnny |
| Season 4, Episode 24 | The Destruction of Johnny X |
| Season 4, Episode 25 | iJohnny |
| Season 4, Episode 26 | Johnny vs. The Mummy |