It was Dundalk's 65th consecutive season in the top tier of Irish football.

A number of key players from the Double-winning 1987–88 season had moved on at the end of 1989–90, and they were joined early on by Tony Cousins, who signed for Liverpool in September.

[3] The 33-round League programme commenced on 2 September 1990, and in the opening match Dundalk were well beaten by Shelbourne, 5–1.

Midway through the season, however, they suffered a shock 1–0 defeat in the FAI Cup to non-League Ashtown Villa.

[5] The league schedule was completed on 21 April 1991 and, in an end of season, winner takes all match in Turner's Cross against Cork City, Dundalk won the title for the eighth time, with the winning goal being scored by cult hero, Tom McNulty.