you just have to work REALLY REALLY hard.......you have to fight high lv Pokemon, and your Pokemon will eventually reack lv100. but that's the highest lv it goes up to.
You can get a level one hundred Pokemon in HeartGold the same way that you can get a Pokemon of that level in other games. You have to level them up until they reach it.
By cheating
In the game you have to battle alot of Pokemon till your Pokemon level up.On a pokewalker a hundred steps is a level up,but your Pokemon can olny level up one.
all level hundred starters,than lvl hundred ledgendaries.
an level hundred
you need about 7 revive and one Pokemon that is level hundred
Keep fighting the Pokemon league or train in cerulian cave
You have to train them a lot, or use Rare Candies.
Because if you had a modifier and it was a level a hundred that wouldn't be fair for other people. byTimera
your never done in Pokemon intell you have all poke mon and all level one hundred
We cant get a hundred level groudon but we can get a ghostly groudon in the cave in the downright part of the page
no it is not its only possible if you migrate a level one hundred Pokemon or trade