Dalseong-wi, royal son-in-law of Seonjo; fourth son of Seo Seong; pen name Songgang; founder of the Dowi-gong branch

| Life | 1579 ~ 1643 |
| Era | 조선 중기 |
| Clan | 대구 서씨 |
Seo Gyeong-ju (1579-1643) was a mid-Joseon official and royal son-in-law of King Seonjo, of the Daegu Seo clan. Courtesy name Jasun, pen name Songgang, he was the fourth son of Seo Seong, with elder brothers Seo Gyeong-u, Seo Gyeong-su and Seo Gyeong-bin (Cheomchu-gong).
Around 1591-1592 his betrothal was agreed with Princess Jeongsin, eldest daughter of Seonjo's royal consort Inbin Kim, and the wedding took place the next year in the midst of the Imjin War, when he was titled Dalseong-wi. He never left Seonjo's side in the war, served concurrently as Chonggwan and director of the Sangeui-won during the second invasion, and rose in rank for overseeing the Royal Genealogy. Under Gwanghaegun he is said to have opposed, with his father, the plan to depose Queen Dowager Inmok.
In 1624 he rose to Sungdeok Daebu (senior first rank) for escorting King Injo. During the 1627 Manchu invasion the princess and the whole family followed Injo to Ganghwa and later returned to Hanseong; after his father's death in 1631 he served as director of the Sangeui-won and Gwansanggam and as Chonggwan. His line is called the Dowi-gong branch, and his grandson Seo Mun-jung became Chief State Councillor.
After the betrothal with Princess Jeongsin the war broke out, and the wedding was held the following year, after which he was titled Dalseong-wi.
He stayed with Seonjo in the Imjin War, rose to Sungdeok Daebu for escorting Injo, and fled with his family to Ganghwa in the 1627 invasion.
His grandson Seo Mun-jung and great-grandson Seo Jong-tae became Chief State Councillors, and Seo Yu-yeong, author of the Geumgye pildam, is said to be a sixth-generation descendant.
The location of his tomb was not confirmed here.
Through his son Seo Jeong-ri his line continues to his grandson Seo Mun-jung and great-grandson Seo Jong-tae, both Chief State Councillors.