This is the long haul single player achievement. You must complete every event in every season as well as all the World Tour events to unlock this achievement. This achievement does not include DC Challenges. When you complete all the events within a competition, the corner should read "250/250" (or whatever amount of points are available) and if you complete the DC Challenge on at least bronze the triangle will turn a golden colour to signify completion. Once you get maximum points in all 4 seasons and 6 world tours, you will unlock this achievement. If also going for completion of all DC Challenges, aim to turn all the pyramids into pure gold.
You can check your progress from the main menu by going into "My Dirt" and then "Stats".