The club received the "Royal" designation upon 25 years of existence, becoming RFC Sérésien.
From 1930 until 1952, the club was playing steadily at the second level of Belgian football, however the following thirty years, the club would hover between the second, third and fourth level of Belgian Football, moving up or down a level roughly every three or four seasons, before finally reaching the Belgian First Division in the 1982–83 season.
The club was able to stay at the top level for five seasons and briefly even dropped back to the third level, before returning to the highest level for the 1993–94 season, immediately finishing in third position, qualifying for the 1994–95 UEFA Cup where the club lost in the first round on away goals to FC Dynamo Moscow.
At that same time, another club from the city, called Royale Union Liégeoise (matricule 23, founded in 1922 and formerly known as RFC Bressoux), renamed itself to Seraing RUL and started playing at the Stade du Pairay where RFC Seraing played until its default, but it is an entirely different club and is entirely distinct from the former RFC Seraing.
As a result, the club was able to immediately jump three levels and started the 2014–15 season in the Belgian Second Division.