Quinn Mallory is a genius student who lived with his mother in their home at San Francisco. His father died having been hit by a car when he was younger. He attended the University of California where he studied Physics and was taught by Professor Maximillian Arturo, who did not realise Quinn's talent. Quinn was working on an anti-gravity device when he discovered Sliding - the opening of an interdimensional vortex and the ability to travel between alternate dimensions. He also had a part time job as a computer salesman working with his friend Wade Wells.
Quinn was born in San Francisco, California in 1974. He was an only child to his parents, Michael and Elizabeth Mallory. His intelligence was soon obvious and first manifested itself as a fascination with dinosaurs and science.
In his later childhood, Quinn's father died when he was hit by a car and he also became bullied at school. In an attempt to stop the bullying he broke the leg of one of the bullies; these incidents had a profound effect on his life. Around this time his dog, Bopper ran away from home and was never found. Later he got a grey cat named Schrodinger, after the famous scientist.
Quinn was a quarterback in high school, but after a leg injury was forced to stop and pursued his interest in science. After graduating he attended the University of California where he was taught by Professor Maximillian Arturo. It was at this time he attempted create the world's first anti-gravity device in his basement. Through Quinn's video diary we see this attempt failed, but instead opened an interdimensional portal through which he could travel to other worlds.
It was on the second slide along with the Professor, Wade and Rembrandt that Quinn was forced to open the vortex before the timer had reached zero, causing the timer circuits to malfunction, and lose the co-ordinates to their Earth (Earth Prime) such that they had to continue sliding to see if they could eventually reach home.
In the second season, the Kromaggs implanted a tracking chip into Quinn in the hopes that he would slide home and reveal the co-ordinates to their Earth so that they could invade. A side effect of the tracking device was suggested by fans as a plausible cause of Quinn's change in personality in the later series. This was infact due to Fox's desire for a change of direction in the show to be more action-oriented and Quinn's character became notably more outgoing and less 'nerdy'.
In the fourth season, the show changed networks and an entirely new storyline was written. In this season Quinn discovers he was not infact born on Earth Prime, but on the Kromagg homeworld and that, in order to avoid being caught in a war between humans and Kromaggs, his real parents slid to Earth Prime and asked Mrs. Mallory to look after him. In addition, Quinn was not infact an only child but had a brother, Colin Mallory, who joined the cast later in the season. It was the writers' intention that Colin was to be a creation of the Kromaggs created from Quinn's DNA, however this crucial plotline had to be ignored when the writers needed a Colin double for what they felt was the best idea of the season, "Lipschitz Live!".
Quinn's time on the show came to an end after Season 4 when Jerry O'Connell did not rejoin the cast for a fifth season. At the start of Season 5, Quinn was 'melded' into his fraternal double by an evil scientist whilst in the interdimensional tunnel between worlds; his mind was now transferred into the double, played by Robert Floyd. Attempts to split the two during the season were not successful.