Weh began his military service as an enlisted Marine before selection for Officer Candidate School. He served two tours in Vietnam and with the British Royal Marines in Malaysia. Colonel Weh was recalled for active duty during the Persian Gulf War, for the U.S. expedition into Somalia, and to serve as chief of staff of Marine Forces Pacific prior to retiring in 1997. In 2003 and 2004. he was again recalled from the USMC Retired List to serve in Iraq and given a key leadership role with the creation and organization of the new Iraqi Army. For his service, Weh received a Silver Star, the Legion of Merit, two Bronze Star Medals, one with V device, a Purple Heart with two gold stars, the Meritorious Service medal with gold star, and five Air Medals.