Doby Tyerell was an Aleena male, specifically from Aleen. He was the offspring of the renowned Podracer, Ratts Tyerell, and the younger sibling of Deland Tyerell.
Following his father's demise during the Boonta Eve Classic podrace in 32 BBY, Doby's older sister, Djulla, was sold into servitude by his uncle. Sebulba, a fellow podracer of Ratts, became her owner. To regain her freedom, Doby's brother Deland agreed to compete against Hekula, Sebulba's son, in an unsanctioned podrace at the Great Dordon Caves located outside of Euceron City. This race occurred at the same time as the Galactic Games of 26 BBY, but was a separate event. Doby served as Deland's race mechanic.
However, Sebulba resorted to his usual cheating tactics and incapacitated Deland's arm before the race commenced. Fortunately, a young Jedi by the name of Anakin Skywalker, a former rival of Sebulba, stepped in to race Deland's vehicle on his behalf. Despite Maxo Vista's sabotage of Deland's podracer, Anakin overtook Hekula's pod to secure victory, thus liberating Djulla and enabling the three happy Aleenas to return to their home planet.
Obi-Wan Kenobi later discovered that Doby and Deland had gained an unfair advantage by acquiring advanced holographic route information (before it was available to the other racers) through a "timing" map provided to their pod by Vista. Nevertheless, even with Vista's sabotage of their pod, Skywalker managed to succeed, and the young Jedi's triumph ensured the Tyerell brothers' sister was freed.
Subsequently, when Deland initiated the Ratts Tyerell Foundation, an organization dedicated to opposing podracing due to its inherent dangers, Doby played a significant role in its operations.