Growing up, art was always encouraged by Walter's parents and upon entering college, made it his goal to pursue art as a career. Walter's artistic passion was focused on comic books and superheroes but at that time, editorial work was the only real option for him. Realizing that editorial work wasn't what he wanted, Walter decided to withhold his artistic career and took up a number of different jobs. From set construction to video game testing, Walter worked any job he could get while still thinking how he would go about pursuing art once again.
After reaching the age of 30, Walter made a serious effort to further improve his artistic skills and create a portfolio that best shows off what his passion was. During all this, Walter was also speaking with other artist, primarily sculptors, which eventually lead him to trying 3D work. With his newly found skill set, Walter finally found an outlet where he can fully express himself which later became the career that he's been looking for.
Source: Sideshow Collectibles