Hyojang was born the son of Yi Geum, Prince Yeoning and later Yeongjo of Joseon, and one of his concubines Lady Lee Jungbin of Hamseong, Changui-kung, Sunhwabang in Hanseong. He was born during the reign of his grandfather King Sukjong. His birth was not made public or reported in the news, because one year before his birth, his grandmother Lady Chol Sukbin died. His mother, Lady Lee Jungbin of Hamseong, was the daughter of Lee Jun-chul, a noble of Joseon. His first name was Man-bok, which was later changed to Haeng. In 1720, King Sukjong died due to dementia and Smallpox sequelae and was succeeded by his son Crown Prince Yi Kyun as King Gyeongjong. As Gyeongjong was childless, Prince Yeoning, Hyojang's father was appointed as Crown Prince. King Gyeongjong died in 1724 and Prince Yeoning was crowned as King Yeongjo of Joseon. Hyojang was then appointed as Prince Kyeongui and in 1725 was appointed to Crown Prince. In 1726, his father selected Lady Hyeon of the Pyungyang Jo clan, a daughter of vice prime-minister Cho Mun-myung and niece of Cho Hyon-myong, also a vice prime-minister, as Hyojang's wife. The two were married but with no issue. In 1728, Hyojang died suddenly in Gyeongbokgung at the young age of 9, after being ill for some months. The cause of his illness was unknown. The prince's death was devastating to his father King Yeongjo, who was sad for some months. Yeongjo then gave his son the posthumous epithet title Hyojang, therefore his title was Crown Prince Hyojang. Hyojang was buried at Mt. Ahyeon, between Yeonhee Kung and Yonsei University and Aeogae station. On January 26, 1729, his grave moved to Neungan-ri at Jori town in Paju.
After death
In 1735, seven years after his death, his half-brother Sado was born and succeeded Hyojang as Crown Prince. In 1762, Sado was imprisoned in a wooden rice chest by the orders of his father King Yeongjo, and died 8 days later, leaving his son Yi San as the royal successor. King Yeongjo was concerned that Yi San, being Sado's son and successor, would be branded with the title of "Son of a prisoner" or "Son of a psycho" and thus become ineligible to succeed the throne, so on February 21, 1764, the King decreed that Yi San would become the adoptive son of the long-dead Crown Prince Hyojang. In 1776, King Yeongjo died of dementia and Yi San succeeded him as King Jeongjo. Surprisingly, on his coronation day, Jeongjo announced to his courtiers, "I am the son of Crown Prince Sado", In spite of this, King Jeongjo did not change the laws of King Yeonjo. Jeongjo later honored Prince Hyojang as an Honor King, and granted him the posthumous epithet title of Jinjong and Great King of Onryangyemyongchulmun. Hyojang's wife Lady Cho Hyunbin of Pungyang was also honored as an honor Queen and given the posthumous epithet title of Honor Queen-consert Hyosun. On July 31, 1907, Hyojang was appointed emperor by Sunjong of Joseon and given the posthumous title of Emperor So Jinjong of the Korean empires.
