Bargewell was born in Hoquiam, Washington and graduated from Hoquiam High School in 1965. During the Vietnam War Bargewell completed Special Forces training and was accepted into MACV-SOG where he served at the "Command And Control North" launch site at Da Nang and served as team leader for Reconnaisance Team "Viper" (all CCN teams were named for states or snakes). While serving with CCN, Bargewell earned the Distinguished Service Cross for his actions in combat. He is currently the last recipient of a DSC awarded for actions in Vietnam remaining on active duty. He then received his officer's commission in 1973. Bargewell also served as a member of the 75th Ranger Regiment, a former commander of Delta Force at Fort Bragg, North Carolina, commander of US Special Operations Command Europe, assistant chief of staff for SFOR military operations in Sarajevo, and the director of the center operations, plans, and policies of US Special Operations Command.
Bargewell pursued an outside administrative investigation as to how knowledge of the Haditha incident in Iraq passed up the Marine chain of command and whether or not any commanders lied in their reports. The informal investigation, pursuant to Army regulation AR 15-6, began on March 19, 2006 and is expected to call for changes in how US troops are trained in its final report. The completed report was sent to Army Lt. Gen. Peter W. Chiarelli, the second-ranked US commander in Iraq, on the morning of June 15, 2006. He will now review the recommendations made and carry out any appropriate actions. This is separate from a criminal investigation being conducted by the Naval Criminal Investigative Service.