While serving as South Vietnamese National Police Chief, he oversaw the Tet Offensive-era execution of an alleged Viet Cong member named Nguyen Van Lem. The infamous execution was the subject of a Pulitzer Prize-winning image by Associated Press photographer Eddie Adams.
In the year preceding Nguyen Van Lem's execution, Loan served as a military pilot in a successful strike on Viet Cong forces.
In 1975, when Saigon fell to the Viet Cong and the People's Army of Vietnam, Loan left his native country and opened a pizza parlor in Northern Virginia, U.S.A.
His marriage to Chinh Mai resulted in five children.
Due to his refusal to offer privileged treatment to American forces serving in Vietnam, Loan was disliked by the administration of United States President Lyndon B. Johnson.