Chief academician and Left Consultant who served six kings; compiler of the Dongmunseon; pen name Sagajeong; posthumous name Munchung

| Life | 1420 ~ 1488 |
| Era | 조선 전기 |
| Clan | 대구 서씨 |
Seo Geo-jeong (1420-1488) was an early-Joseon civil official and scholar of the Daegu Seo clan. Courtesy name Gangjung (early courtesy name Jawon), pen names Sagajeong and Jeongjeong, posthumous name Munchung, he was a son of Seo Mi-seong and a maternal grandson of Gwon Geun. His sister married Choe Hang, and his elder brother was Seo Geo-gwang, Magistrate of Eonyang.
He passed the civil examination in 1444 under Sejong, began as Jikjang at the Sajaegam, took study leave in 1451 and served as doctor and Eungyo of the Hall of Worthies. He passed the second examination in 1456, topped the 1457 palace test, and in 1460 went to Ming China as an envoy, where scholars are said to have praised him as a rare talent of Korea. In 1464 he became the first joint chief academician of both the Hongmungwan and Yemungwan, and topped the 1466 Baryeong examination. After serving as minister of every one of the six ministries, he became Left Consultant in 1470 under Seongjong and the next year was enfeoffed as Lord of Dalseong as a third-class Jwari merit subject.
He served six kings from Sejong to Seongjong for nearly 45 years and excelled at poetry, prose and calligraphy. He left the Dongmunseon, a high point of Korean poetry criticism, and the tale collection Pilwon japgi, and took a deep part in compiling the Gyeongguk daejeon, Dongguk tonggam and Dongguk yeoji seungnam. He is also said to have translated the Hyangyak jipseongbang by royal command. After death he received the name Munchung and was enshrined at Guam Seowon in Daegu; Sagajeong Station on Seoul Metro Line 7 is named after his pen name.
Seo Geo-jeong was the second son of Seo Mi-seong, with an elder brother Seo Geo-gwang. His mother was a daughter of Gwon Geun, and his sister is said to have married Choe Hang.
He held both academies' chief posts from 1464, served as minister of all six ministries and rose to Left Consultant. He is described as versed in poetry, calligraphy, geography and medicine.
The Dongmunseon gathers poetry and prose from Silla onward; he also left the tale collection Pilwon japgi and the poetry criticism Dongin sihwa, and took part in compiling the Gyeongguk daejeon, Dongguk tonggam and Dongguk yeoji seungnam.
The location of his tomb was not confirmed here. He is said to be enshrined at Guam Seowon in Daegu.
The Saga-gong branch is said to take its name from his pen name. He is regarded as the most representative figure of the Daegu Seo.