When creating a custom character you are able to choose your character's base power. There are many base power's to choose from and each power will tell you what role your character will be best suited for.
There are number of Controller powers to choose from but currently the only free Controller powers to select are Gadgets and Mental. I'm not sure if the other powers become available automatically when you pay for a membership but will update the solution if I hear one way or the other.
Upon reaching level 10 this achievement should unlock but there is a chance that the achievement will not unlock on time. If you hit level 10 and are not awarded with an achievement you will need to simply back out to the character select screen and then log back into the game, at this time the achievement should unlock instantly.
For the purpose of full discloser, I have not yet attained this particular achievement but did earn the achievement for reaching level 10 for the healer role and this is what I experienced with that achievement and it should work here as well.