Sanjay's step father is a tough military soldier who lives in an army base in Dimmsdale. The markings on his uniform and his manner of speech suggest that he is in the United States Marine Corps. He resembles a human version of Jorgen but his arms are much bigger in proportion to his body.
He wears a green camouflage military cap and uniform. He has huge arms and a massive chin. He says he is not very good at math and this is examplified when he loses count of Timmy Turner's sit-up reps (causing him to start over every time he loses count) and that is why he joined the military. Due to his skin tone, it can be assumed that he is also of Indian descent (like his stepfamily).
He has a son named Alexander who is also in the military, and Sanjay is his step son through marriage to his mother. He trains Sanjay early in the morning every day by making him do military-style physical work outs (Sanjay seems to be used to this since he had no complaints against this). Other than that, not much is known about him and he rarely appears in the series.
It was never revealed in the series who Sanjay's biological father was, although during the episode School's Out!: The Musical, a man of possible Indian descent is standing with Sanjay's mother and could possibly be him, but it was an extremely brief shot and there was nothing said during it to confirm this.