My Xbox 360 and Xbox One Gamertags are separate - Microsoft Community

Gamertag Lookup: Find the Tag You're Looking For

Fix: Can't Change Gamertag for Xbox Community

Xbox Gamertag Update Lets You Take Someone Else's Name With One Key Distinction - GameSpot

There is a way around the new gamertag systems character cap, if you change your gamertag on 360 it allows 15. : r/xboxone

Still want a 15-character gamertag? Use an Xbox 360 to create it

Microsoft Xbox 360 Console with Wireless Controller Call of Duty: Modern Warfare 2

I seem to have two different gamertags on the same account, and I'd - Microsoft Community

How to change your Xbox Gamertag - Android Authority

Xbox network, Microsoft Wiki

Xbox one changes 9.99 to change your gamertag : r/assholedesign