Triple H was first known for wrestling in WCW as Terra Ryzin but didn't gain much popularity there. He left for the World Wrestling Federation and ended up there under the name of Hunter Hearst-Helmsley. He portrayed a rich snob-like character and had a big feud with Duke "The Dumpster" Droese. After a few years he won a few titles and became the King of the Ring in 1997. He then joined up with Shawn Michaels under the name of Triple H (stands for his former name). They started D-Generation X, a group who doesn't listen to authority and does whatever they want.
After Michaels left the group, Triple H became the leader and they got new members. After great success of the group, especially with their feuds against the Nation, they broke up and Triple H received the WWF Heavyweight Championship. He then ended up marrying Vince McMahon's daughter Stephanie in a sneaky manor. He continued his reign at the top of the WWF until he got a knee injury where he was gone for about six months of 2001. He came back stronger than ever and has become the second undisputed World Champion.
His future looks to be as bright as his past, so expect more championships from Triple H in the future!