After graduating from Tulane University, Special Agent Robert C. Lightfoot worked for the U.S. Agency for International Development in Vietnam and Thailand. He assisted the Thai Border Patrol Police before joining the Drug Enforcement Administration in 1974. Agent Lightfoot was fluent in Thai and worked in DEA's Chiang Mai Resident Office in northern Thailand. This experience assisted him greatly in his role as liaison between DEA's Bangkok office and the Royal Thai Government.

In 1975, he was assigned to the Los Angeles Field Division, where he worked in DEA's first Clandestine Laboratory Enforcement Group. In 1977, Special Agent Lightfoot was reassigned to the DEA Bangkok Office. Three months after his arrival in Thailand, Special Agent Lightfoot was killed as a result of an accidental discharge of his firearm. He was 34 years of age at the time of his death.

A school for the hearing impaired was established in his honor in Chiang Mai, Thailand, and the school still bears his name. In addition to loving his career, Special Agent Lightfoot had an avid passion for tennis. While at Tulane, he played competitively on the collegiate team and continued to play regularly all his life. During his association with the sport, Special Agent Lightfoot taught actor Steve McQueen how to play tennis.