You get this achievement for completing all of the challenges in the game. The challenges you need to complete are:
-33 Team Challenges
-9 Deathraces
-12 Films
-6 Getting Started
-20 Hall of meat
-11 Own the Lot
-16 Own the Spot
-18 Photos
-19 Pros
-20 Team Promos
-9 Street Contests
-16 Training
-9 Tranny Contests
Killing the challenges is not needed, you just need to own them all.