Their repertoire included rock and roll, country and western, Dixieland jazz, big band tunes, Irish Céilí dances, Latin, folk, and more.
Many such bands toured in Ireland, and some of the successful ones later performed in Britain, the US, Canada, on the German nightclub circuit, and on U.S. military bases in Europe.
Instrumental music was their main focus, providing the backdrop to a night of dancing that might be five hours long (e.g., 9 PM to 2 AM).
The Maurice Mulcahy Orchestra went from fifteen members in the early sixties (five saxophones, four trumpets, one trombone, rhythm section and a singer) to ten members in the early seventies, which included two singers but still held four saxophones and one trumpet, a large brass section for the seventies.
Strabane's Clipper Carlton are credited with being the first to incorporate a 'show' in the middle of their act, 'Duke Box Saturday Night', where they imitated the hits and singers of the day.
Brendan Bowyer, Tom Dunphy and the Royal Showband from Waterford toured professionally around 1958, and became a crowd-drawing success.
They were managed by promoter T. J. Byrne, and were the first such band to have a record enter the Irish charts, "Katie Daly", sung by Dunphy.
Many would consider Brendan Bowyer the "king" of the showband era, for his powerful and attractive voice, his handsome good looks, and his energetic dance moves on stage.
First singing with Dublin's Strykers, Blackbirds, Echoes and Melochords, he became a star with The Miami Showband, and in 1966 represented Ireland in the Eurovision Song Contest.
A second wave of bands emerged in the late sixties and early seventies with personnel coming mostly from the beat-groups scene.
Some even demanded a percentage of the door takings from the ballroom operator, the amount depending on how popular the band were.
It became riskier for ballroom operators to run dances and make a profit with falling attendances and increased fee demands from bands.
Cross-border band touring dropped significantly as a result, hastening the general decline of the showbands.
In the North East, the Adelphi ballroom, owned by Dee O'Kane and Jimmy Hamilton in Dundalk, attracted audiences from both sides of the border.