Union Luxembourg was formed in 1925 as an amalgam of US Hollerich Bonnevoie and Jeunesse Sportive Verlorenkost.

Although US Hollerich had been one of the top clubs in Luxembourg, winning five titles consecutively, by 1925, its success had dried up.

However, that all changed very swiftly, as Union hit its stride, beginning with another cup victory in 1959.

Luxembourg won three National Division titles back-to-back between 1990 and 1992 and returned to the habit of European qualification.

As it happens, Union was relegated in 2004–05 (as was Spora), marking an unfitting end to one of Luxembourg's most successful clubs.