Johannes Leimena, more colloquially referred to as Om Jo, was an Indonesian politician, physician, and national hero. He was one of the longest-serving government ministers in Indonesia, and was the longest-serving under President Sukarno. He filled the roles of Deputy Prime Minister and Minister of Health. An Ambonese Christian, he served in the People's Representative Council and the Constitutional Assembly during the 1950s, and was the chairman of the Indonesian Christian Party from 1951 until 1960.

National Hero of Indonesia is the highest-level title awarded in Indonesia. It is posthumously given by the Government of Indonesia for actions which are deemed to be heroic, defined as "actual deeds which can be remembered and exemplified for all time by other citizens" or "extraordinary service furthering the interests of the state and people". The Ministry of Social Affairs gives seven criteria which an individual must fulfill, as follows:Have been an Indonesian citizen who is deceased and, during his or her lifetime, led an armed struggle or produced a concept or product useful to the state; Have continued the struggle throughout his or her life and performed above and beyond the call of duty; Have had a wide-reaching impact through his or her actions; Have shown a high degree of nationalism; Have been of good moral standing and respectable character; Never surrendered to his or her enemies; and Never committed an act which taints his or her legacy.