Rom, older brother of the scheming and profit hungry Quark, is a somewhat simple and unassuming Ferengi. He's not your typical Ferengi, for he puts kindness and consideration above profit.
He proves himself more than just a go-for for his demanding brother. We learn he has a talent for fixing all things mechanical, disproving Odo's assertion that he couldn't fix a bend in a straw. He is made an engineer on the station, working closely with the Chief Engineer Miles O'Brien. He even catches the heart of a Bajoran Dabo Girl named Leeta and they marry.
One turning point for Rom is forming a union when his shitty boss Quark refuses to give him time off for a serious ear infection caused by too much oomax (the Ferengi version of masturbation). He gathers grievances from all of Quark's employee's including Leeta, and challenges not only Quark, but the Ferengi Commerce Authority (FCA). And it helps to have an ally like Benjamin Sisko to give them the freedom to go on strike.
At the end, he is made Grand Negas when Zek retires, ushering in new equality era for Fereginar.