Marcello was the head chef at Coal, the restaurant where Auggie Kirkpatrick worked. He was hard to impress and strict. In the past, he had hired Auggie as a favor to Sydney Andrews. He reluctantly hired Violet Foster when she applied for a hostess job at Auggie's request.
He hired David Breck as a temporary employee, but David got into a brawl during his first night and Marcello fired David and warned Auggie. He later harshly rejected a dish Auggie prepared for the menu, despite Violet giving great reviews for it. He later stole the dish and presented it as his own.
Later, after Marcello got a look at Riley Richmond, he talked about her sexually to the point where Auggie physically attacked him and lost his job.
A few weeks later, David bought the restaurant and fired Marcello.