Right State Councillor under Injo; eldest son of Seo Seong; pen name Mansa; founder of the Mansa-gong branch

| Life | 1573 ~ 1645 |
| Era | 조선 중기 |
| Clan | 대구 서씨 |
Seo Gyeong-u (1573-1645) was a mid-Joseon civil official of the Daegu Seo clan and the eldest son of Seo Seong. Courtesy name Sibaek, pen name Mansa (晩沙), from which the Mansa-gong branch is said to take its name.
He passed the civil examination in 1603 under Seonjo and began as Gajuseo, then served as recorder at the Royal Secretariat, Seonggyungwan official, Inspector, and assistant section chief in the ministries of Works, Military Affairs and Justice. He was a literary tutor to the Crown Prince and held Jipyeong and Jeongeon posts, but was stripped of office by the Great Northerners under Gwanghaegun, then returned as Participant in the Ministry of Rites. He later held key posts as royal secretary, Remonstrator-General, Vice Minister of Personnel, Inspector-General, Gyeonggi governor and Principal of the Seonggyungwan.
Under Injo he served as Minister of Justice and became Right State Councillor in 1644, dying the next year. His portrait and its case are designated Treasure No. 1897. His son Seo Won-ri served as governor of Hamgyeong Province, and Seo Mun-jung, later Chief State Councillor under Sukjong, was adopted into this house and carried on the line.
After passing the examination in 1603 he was briefly stripped of office under Gwanghaegun, but under Injo served as Inspector-General, Vice Minister of Personnel and Minister of Justice before becoming Right State Councillor.
His portrait and case are Treasure No. 1897, introduced together with the portrait of Seo Mun-jung (Treasure No. 1898) as portrait heritage of the Daegu Seo.
The location of his tomb was not confirmed here.
His son Seo Won-ri (governor of Hamgyeong) and the adopted heir Seo Mun-jung (Chief State Councillor).