The movement to create Seoul United FC began in 2001 as a group of supporters set about bringing professional football back to the city of Seoul, following the K League's decision to relocate the then-capital clubs to other cities.
Despite this, the fan push continued and the establishment of the K3 League in 2007 gave a realistic opportunity for involvement in the league set-up. Two amateur sides, Good Bu&Bu (Good Friend) and Youngseo FC (Jin Seoul), were merged to create the new club and the home venue of Seoul Olympic Stadium was chosen. Since 2010, Seoul United FC moved to home stadium to Hyochang Stadium
The club's first ever match was played on April 21, 2007, a 2–2 home draw with Changwon Dudae FC.