Given that I’ve been asked about this more than once, let’s look at the purpose of a WordPress username and how to update it.
Your username serves two purposes. First, it’s your website administrator login (the “back end”). Second, it’s the public name that will appear on your blog and other places online (the “front end”). There are two ways to change your Username.
1. Keep the same login and simply change your public display name. I recommend this option for most users.
Go to Dashboard> Profile > My Public Profile. Scroll to “Display name publicly as” and enter your name the way you want. Then click the Update button up top.
2. Change your username completely, for both in the back and front ends .
Go to Dashboard> Profile > Personal Settings > Scroll to Account Details. Then Change “Username.”
Why you’d want to rethink this carefully: it will change your logins and affects other functions like your Gravatar (public identity system used on WordPress and on other places in the web).
Read more about both options on my Blundr.

