He/she would have to be in the history books that would be read in the future
How many people do we remember from 1000ad to 1500 ad. I think most people would struggle to name 10 . From 1500ad to 1900ad we would have people like Napoleon and various heads of states. People who kill a few million or more might be remembered though it is not guaranteed.
The world is becoming more global so in some future time we might have a federation...a type of world government, which could have enormous benefits for mankind . The sums saves on wars and weapons could be diverted to the benefit of mankind.If such a humane regime took control the first leaders would be hailed worldwide for millenia afterwards. The previous era would be dismissed as a barbarian warlike era.This new era could manage the world finances much better and of course a new codes of conduct would be established becoming a quasi religion with new leaders.Sporting stars and musicians would come and go.I mean kids today only know the players who are currently playing with their county team or the national team.
Serious brains who threw deep insight into an important area would be remembered like darwin,einstein,etc.
The internet and the www has as I understand it many fathers and each country has its own inventor of the computer, so no one is going to be remembered for that just as no one knows who invented the wheel or the bow and arrow.