Prem Tinsulanonda played a highly significant role in modern Thai history. From 1978 until his death in 2019, he exerted 40.5 years of enormous sway over the Thai military and Thai politics, including a stint as unelected prime minister from 1980 to 1988, and afterwards becoming the dominant force on the king's Privy Council. Moreover, officers close to Prem or who earned his trust ascended to leading military positions. His endorsement was necessary for the appointment of seventeen out of the eighteen army commanders who followed him after 1981—with the exception of Thaksin Shinawatra's cousin Chaisit Shinawatra (2003–4).

Prem was a follower and admirer of Krit Sivara. But Prem's devotion to Krit owed not to the former's support for Krit's coming out against the dictatorship of Thanom/Praphas. Rather, it was to Krit's ability to develop a structure for the preparation and management of counterinsurgency when the latter was commander of the 2nd Army Region (1960–63), 1st Army Region (1963–66), deputy army commander (1966–73) and army commander/supreme commander (1973–75). Following Prem's 1978 appointment as army commander, in February 1979 the Royal Thai Army camp in Sakon Nakhon was named after Krit to commemorate his successful prosecution of counterinsurgency in the Northeast. In March 2014, Prem christened a monument to Krit within the camp out of respect for his leadership against the insurgents. But despite Prem's allegiance to Krit, he led Thailand's military away from the democratic reformism that Krit had supported.

Indeed, Prem owed to Krit his early rapid rise in the military. Six years Krit's junior, Prem was not a product of Bangkok's elite military families. He was born on 26 August 1920 in the southern province of Songkhla. His father, Bueng, was a moderately high-level bureaucrat who served as the warden of Songkhla prison and eventually rose to be a deputy chief of staff in the Interior Ministry. Following in the tradition of all mid-ranking to senior civil servants at the time, Bueng was bestowed a surname by then king Rama VI.