You can't, even with hacking.
There is no such code for that. The game can only allow you to have Pokemon up to level 100. No Pokemon over level 100 exists.
Train your pokemon.
1829390583759780
The highest a pokemon could be is level 100.
level 100
NO. There is not. That would be cool if hey do
ergfergfs
No, you cannot.
any level up to 100
easy just cheat
No Pokemon can reach a higher level of 100 in Pokemon diamond or pearl even if you use action replay, i don't think you can get it sorry :( nintendochick knows all!
beat him with a level 100