Steam will always keep a history of the various aliases you may have used throughout your playing career. You can check what your aliases have been over time, in addition to being able to see the aliases of any Steam user, whether or not they are on your friends list. Steam accounts set to private will not display most types of information, including old aliases.
To view someone’s Steam aliases, you need to access their profile page. You can view the profile of any friend by opening your friends list, right-clicking on a friend and selecting “View Profile”.
You can also do this with any account if you know the original username for that account, which is different from the alias used by the account. Using any browser, go to https://steamcommunity.com/id/ and insert the person’s profile name after the last slash.
Once you view someone’s profile, you can view all of their aliases by clicking the down arrow to the right of their username. If you are logged into your Steam account via the desktop client or the website and you are viewing your own profile, you can delete all of your previous aliases using the “Delete Previous Aliases” button at the bottom of this drop down list – menu down.
Some people change their Steam aliases for fun, some for team names and others for other reasons. If you want to get rid of your aliases, this quick method only takes a few clicks.