You have to get to saffron city and defeat the team rocket in Silph .co defeat the team rocket boss giovanni and then the boss of silph gives it you as a reward
Help silph co then talk to the president he gives the masterball to you.
From the Lottories.
you can use action replay code manager or you defeat Cyrus in team galactic warehouse and he will give you a masterball
You can only get another masterball if a friend trades you a Pokemon holding the masterball they obtained.
Save Silph Co., Just like in Blue.
You run into entei randomly and use a masterball
The only way to get more masterballs without cheating is to have other leafgreen versions or firered or ruby or sapphire or emerald or Pokemon colosseum or Pokemon xd gale of darkness trade the masterball that those games get to leafgreen other than that you have to win the lottery in ruby and sapphire and emerald at lilycove city to get another masterball then trade it to leafgreen.
go into UN inhabited plain and go to the end and zapodos will be there
Yeah go to route 1 until you find it then use the masterball.
You CAN'T make a masterball but you can win one at the Goldenrod Radio towerGo to Front desk. Main stuff is chance, hope, lots of pokemon (increases your chances) and then...YOU HAVE WON NUMBER ONE PRIZE MASTERBALL IF YOU ARE VERY LUCKY!!!!!
It isn't meant for any one pokemon. Most people use it on Mewtwo, which you probably should use it on. You can catch the legendary birds and Mewtwo without a Masterball but it can take a long time.
mew-two is lvl. 70 in cerulian cave. make sure you save a masterball for him