After DeLeon's daughter survived meningitis in 1984, he was involved in the establishment of the Emergency Medical Services for Children program.
Upon DeLeon's retirement, Inouye credited him with working to improve education in Hawaii and with furthering public awareness of the importance of psychologists, nurses and other health providers.
An APA award in DeLeon's name honors a graduate student who contributes to the advancement of pharmacotherapy in psychology.
After finishing his PhD, DeLeon moved to Hawaii and took a job with the University of Hawaiʻi at Hilo's Peace Corps training program.
Though his daughter survived, DeLeon learned that the average hospital emergency room was not equipped to deal with seriously ill infants or their families.
While he served on the APA Board of Directors, DeLeon and Inouye were largely responsible for a 1988 legislative measure that authorized psychopharmacology training for United States Department of Defense psychologists.
[7] According to Inouye, DeLeon also played major roles in the development of the schools of pharmacy and nursing at the University of Hawaiʻi at Hilo.
[20] He is the recipient of honorary doctorates from Nova Southeastern University, the Forest Institute and the California School of Professional Psychology.
[21] The Patrick H. DeLeon Prize was established by Division 55 of the APA to honor a graduate student who makes significant contributions to advance pharmacotherapy in psychology.