See Ask Questions First, Shoot Later for more info.
This achievement goes hand in hand with sparing everyone you can, so you will probably unlock this around the same time as Ask Questions First, Shoot Later. Unlike this achievement, you need everyone to either like you, or at the very least be neutral with you. Everyone also includes Leland, so you do need to get him to like you enough to offer you a position within Halbech, and you have to accept.
After finishing off the final boss, you will be given the choice between betraying or staying loyal to Leland. Choose to betray him, otherwise you won't get this achievement. If you're following the road map, punch him for Ask Questions First, Shoot Later.