A Gamertag is a person's online character over Xbox live. If you are a gamer and regularly play games, then I am sure you might have played games on Xbox also. Xbox game needs a username called Gamertag. A Gamertag is a username in the gaming world for your Xbox Live record. Using this unique Gamertag, players can identify you, and it helps your fellow gamers to distinguish yourself from others to bond and form teams.