He is the CEO and owner of the Saybrook Empire and a prominent member of the New York society. He is the husband of Penelope Keating, with whom he had two daughters with, Aster and Corinne. He also had an affair with Julia Gilchrist, which resulted in the birth of his third and illegitimate daughter, Danielle Gilchrist.
He attended Steven Barnett (Book Character)'s funeral with the rest of his family.
Five-years-later, he attended Skylar's birthday party and argued with Poppy, which Rowan found odd since he had taken her under his wing after Poppy's parents died. A few days later at the Wednesday family dinner, he scolded Aster for texting at dinner and talked playfull with Poppy.
Following the revelation of Mason's affair, his wife left him and went to Connecticut and the two had yet to speak. Luckily for Mason, she remained poised and didn't make a comment about the whole incident. However, Aster believed she was just too angry to comment. Mason called Aster into his office following her "medical leave" from the company and apologized to her for being absent during all those times that he needed her. Aster didn't find this comforting and lashed out at him while he tried to reason with her.