Quinn Mallory was born in San Francisco, California. At his young age, he skipped two grades in school since he was considered as a young genius. However, he was bullied due to his intelligence and yet he didn't have any friends. But Quinn had a crush on his home school teacher. Later, Quinn decides to teach the bullies a lesson by hitting one of them with a baseball bat. Quinn had only his mother, Amanda Mallory who took care him since his father died.
Discovery of Sliding
During his college years, Quinn spents time in the basement working on his experiments. While working, Quinn creates a device called a timer. The timer is used to create a portal that allows instant travel to parallel dimensions. Quinn was excited to make his startling discovery and decided to take a test by sending himself into the portal. While sliding himself through the portal, Quinn realizes that he made his calculations wrong. He thought he was still on his own world. However, when he was driving, he noticed that the traffic lights were changed and saw a billboard poster of Elvis Presley who is still alive. He also finds that his mother is pregnant with a garderner. Quinn realizes that he is in a parallel world and decides to go back and tell his college professor, Arturo. When he came back, he finds that his parallel double have entered his world and caused trouble for his girlfriend, Wade Welles and Prof. Arturo. Quinn's parallel double turned out to be a slider who came from his world where he was married to his fiance'.
After revealing the secrets of sliding, Prof. Arturo and Wade Welles were amazed and decided to go to another Earth with Quinn. However, a singer named Rembrandt Brown accidentally drove his car through a passing portal and finds himself with the rest of the sliders on the Ice Age world. Later, Rembrandt blames Quinn for him getting involved in this mess since he was about to make his singing performance. The sliders travels to another Earth and later finds out it's not their world. While sliding through other Earths, Quinn faces his parallel doubles with different character and personality.
Over the years of sliding, Quinn learns about his true parents who actually left him on Earth Prime. Quinn learns that he is from a parallel Earth where the invasion of the evolved-human race called the Kromaggs occured. During this invasion, Quinn's parents left him due to the care of their parallel doubles on Earth Prime. When Quinn's parents came back to get him, their doubles decided to keep him hidden and safe since they were so close to him. Quinn also learns that he had a brother named Colin Mallory who was transported to another Earth where technology was resisted.
In Season 5, a mad scientist named Dr. Oberon Gieger experimented on Quinn's fraternal double, Mallory whom he couldn't walk due to his leg injury. However, Dr. Gieger can cure Mallory by merging his double, Quinn into his body. The experiment worked and Mallory was able to walk again until he found out that Dr. Geiger was planning to merge parallel universes together all along.