Doherty was the second of three children born to Bernard and Barbara Doherty. He trained as a pilot at Embry–Riddle Aeronautical University before moving to Snowbird, Utah for several winters and then joining the United States Navy in 1995. Doherty served as a Navy SEAL sniper and Corpsman, responded to the bombing of USS "Cole" and had tours of duty in Iraq and Afghanistan. He left the Navy in 2005 as a petty officer first class and joined the CIA. After leaving the Navy, he worked for a private security company in Afghanistan, Iraq, Israel, Kenya and Libya. He was centrally involved in the rescue of PFC Jessica Lynch from Iraqi forces in 2003 and the rescue of Captain Richard Phillips from Somali pirates in 2009. In the month prior to the attack, Doherty as a contractor with the State Department, told ABC News in an interview that he personally went into the field in Libya to track down MANPADS, shoulder-fired surface-to-air missiles, and destroy them.