You will advance in Rank by completing games in War Rock. With advancement comes privileges; better equipment will be unlocked in the Armory at certain Ranks, and some special events will have a minimum rank requirement. Your Rank will be consistent across all professions.

Private Second Class
Private First Class
Corporal
Sergeant
Staff Sergeant
Sergeant First Class
Master Sergeant
Second Lieutenant
First Lieutenant
Captain
Major
Lieutenant Colonel
Colonel
Brigadier General
Major General
Lieutenant General
General