To gain this achievement you are required to finish the Vice Kings quest lines. This includes all missions and strongholds. (All yellow territories need to be purple.)
The Vice Kings are lead by a very respected man named Benjamin King.
The gangs fly their flags of yellow as their gang color.
You are led against the Kings by Johny Gat (The coolest person ever in both Saints Row 1 & 2)
There are 11 Vice King missions and 5 strongholds to complete for this achievement.