The nickname 'devil dog' has a history in the Marine Corps dating back to World War I during the Battle of Belleau Wood.
Retired Lt. Colonel and current MCLB Executive Director Kent Morrison says there was one particular day where the Marines lost more men that they had during their entire history because of the vicious fighting. We lost over 5,000 marines killed or wounded during the Battle of Belleau Wood, but we were successful. We were victorious at a high cost. At the end of the battle because of the ferociousness that we fought the Germans nicknamed us 'teufel hunden TM. Teufel Hunden stands for ~devil dog TM and we have been devil dogs ever since says Morrison.
The nickname is like a badge of honor for marines past and present not to glorify war, but to glorify the warrior spirit of the marines. Modern day marines continue to call each other 'devil dogs' because it reinforces who they are. It brings us back to our full tradition. Marines today can be devil dogs because of the Marines in the past who earned it for us says Morrison.