You can. As the other commenter wrote `firefox -no-remote -P` works. You can also add the name of a profile after the "-P" to launch directly into that profile.

You can. As the other commenter wrote `firefox -no-remote -P` works. You can also add the name of a profile after the "-P" to launch directly into that profile. If you're not on Windows, you can also instead use `firefox -new-instance -P`, which is better, because -no-remote cuts off communication from other applications to that Firefox instance, meaning that you can't open links from those other applications inside a Firefox instance that's been started with -no-remote. The aforementioned "about:profiles" also has a button "Launch profile in new browser", which is much easier than the above methods, but those are useful, if you for example want desktop shortcut for your individual profiles.