The organization came about during a ritualized period of cleansing observed by Deep Space 9's entire Bajoran crew. Since this involved a period of isolation from regular life, business was seriously reduced with the absence of the Bajorans.
Quark decided to implement cost-cutting measures, including a one-third pay cut for the entire staff. To everyone's disgust, Quark did not even give any assurances that he would reverse the pay cuts when business picked up. Upon hearing about the situation, Dr. Julian Bashir and Miles O'Brien suggested to Rom that he should form a union in response, but also cautioned that violence was not unknown in labor disputes (see also Sean Aloysius O'Brien).
Nevertheless, Rom decided to proceed with the idea, and convinced the rest of the staff (including the Ferengi waiters, Broik, Grimp, and Frool) to form the Guild of Restaurant and Casino Employees. They confronted Quark with their demands, and when he flatly refused, Rom immediately called for a strike – much to Quark's shock.
The strike lasted for days, with Captain Benjamin Sisko refusing Quark's request to intervene. In response, Quark unsuccessfully attempted holographic substitutes for the staff, while Bashir and O'Brien quietly supported the strike by trying to convince patrons to avoid the bar during the labor action. Quark also attempted to bribe Rom to end the strike, but Rom would not end the strike until Quark agreed to every one of the Guild's demands.
Eventually, Brunt of the Ferengi Commerce Authority arrived to break the strike, along with a pair of Nausicaan guards. When his attempt to intimidate the union failed, he had Quark beaten as an example against defiance. In the Infirmary, Rom and Quark debated the situation, with Rom refusing to budge and Quark warning that the FCA was willing to physically attack the union to stop the strike. A compromise was reached, where Quark secretly agreed to the Association's demands – on the condition that the union be immediately disbanded. The union agreed to the proposal, and business returned to normal. (DS9: "Bar Association")