Lou Langlais was born on October 5, 1966, in Quebec, Canada, and grew up in Santa Barbara, California. He enlisted in the U.S. Navy on June 11, 1986, and completed basic training at NTC San Diego, California, in September 1986. His first assignment was aboard the guided-missile frigate USS Wadsworth (FFG-9) from September 1986 to January 1989, followed by Basic Underwater Demolition/SEAL training at NAB Coronado, California, from February to October 1989. Petty Officer Langlais attended Boatswain's Mate training from October to November 1989, and then served with SEAL Team THREE at NAB Coronado from November 1989 to January 1997, during which time he deployed aboard the amphibious transport dock USS Denver (LPD-9) to Southwest Asia in support of Operations Desert Shield and Desert Storm from November 1990 to August 1991. His next assignment was with the U.S. Navy Parachute Team "The Leap Frogs" from January 1997 to February 2000, followed by service with the Naval Special Warfare Development Group at Dam Neck, Virginia, from March 2000 until he was killed in action when the CH-47 Chinook helicopter he was aboard was shot down in Afghanistan on August 6, 2011. During this time, Master Chief Langlais deployed to Afghanistan in support of Operation Enduring Freedom and to Iraq in support of Operation Iraqi Freedom multiple times. Lou Langlais was buried at Arlington National Cemetery.

His 1st (of 6) Bronze Star Medal w/Valor Citation reads:

For heroic achievement in connection with combat operations against the enemy while assigned as a member of a Joint Task Force conducting special operations in support of Operation ENDURING FREEDOM from 3 January to 22 April 2003. Chief Petty Officer Langlais demonstrated extraordinary heroism and composure during an assault on an enemy compound. As his team approached their security overwatch positions, they came under heavy fire. Chief Petty Officer Langlais immediately dropped into cover and began to return fire. As his team leader was gathering information on the contact, Chief Petty Officer Langlais maneuvered himself into a more advantageous position and began to effectively suppress the enemy fire. This afforded his team the opportunity to move out of the fire zone, and the action was concluded with the surrender of all enemy personnel. Chief Petty Officer Langlais conducted numerous combat reconnaissance patrols and other actions against a sophisticated enemy under the constant threat of ambush. By his zealous initiative, courageous actions, and exceptional dedication to duty, Chief Petty Officer Langlais reflected great credit upon himself and upheld the highest traditions of the United States Naval Service.

The Combat Distinguishing Device is authorized.