A young club, it was only formed in 1997 as an amalgam of Union Sportive Bascharage and Jeunesse Hautcharage.

On their first tie in Europe, they suffered the largest ever aggregate defeat in UEFA competition: 21–0 against Chelsea.

Which to this date, is the largest ever aggregate score for an official UEFA football match (but is equal with Feyenoord Rotterdam, who achieved the very same result against US Rumelange winning first leg 9–0 and second 12–0 in 1972–73 UEFA Cup) After losing the previous season's cup final against F91 Dudelange U.N. Käerjeng '97 qualified for the UEFA Cup for the second time in the club's history, drawing Norwegian side Lillestrøm in the first qualifying round.

Losing merely 2–1 away at Åråsen stadion in itself was a remarkable feat for the club, but after a very surprising 1–0 win at home, U.N. Käerjeng '97 was through to the second qualifying round on away goals after a 2–2 aggregate score.

Thus, Käerjeng's overall European record is: Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.