The character of Walter White in Breaking Bad is not directly based on a specific real person, but creator Vince Gilligan and the series writers were inspired by several real-life events and circumstances. Walter White's character was primarily born out of Vince Gilligan's personal musings during a period of unemployment about what he would do to sustain himself financially. Gedankenexperiment served as an inspiration for creating this character – what if a person, like a chemistry teacher, was forced into illegal activities due to financial difficulties? While his character presents a unique combination of elements that fit the narrative of the series, there have been real-life instances of educators or individuals from similar respectable professions turning to illegal activities due to various circumstances. That said, the complete transformation that we see Walter White go through is highly fictionalized and chiefly serves the dramatic needs of the story. Certainly, Gilligan and the writers used a solid scientific basis to back up many of Walter White's exploits. They consulted extensively with the chemistry community (notably, Donna Nelson from the University of Oklahoma) to ensure much of the science was accurate, or at least plausible. This all contributes to making the character believable and grounded, despite the series' many dramatic twists and turns. So, no singular person served as an inspiration for Walter White, but a mix of real-life issues, scenarios, and diligent research played a significant role in sculpting this iconic character.