Prior to his appointment, Tan was the 24th commandant at the PCG. His previous positions included Coast Guard staff for intelligence and operations, vice commandant for administration, and vice commandant for operations.
Concurrent with his position as coast guard vice commandant for administration, Tan commanded the Coast Guard Fleet (formerly the Maritime Security and Law Enforcement Command), the largest unit of the Coast Guard.
He obtained his Master of Science in Maritime Affairs in 2002 at the World Maritime University in Malmo, Sweden. He was high school valedictorian at Negros Oriental State University in Dumaguete City and was an American Field Service exchange student from 1973 to 1974. He also attended numerous courses on maritime safety and environment in different countries.
Tan received numerous service and national awards, including the Coast Guard Legion of Honor, Coast Guard Outstanding Achievement Medal.