Jinkins was born in Richmond, Virginia, and lived there during his childhood. His experiences growing up in Richmond would serve as an inspiration for the fictional town of Bluffington, Virginia, in the series Doug.
Later, Jinkins worked in advertising, creating TV commercials and promotions featuring a young boy and a dog, who would become the main characters of his major creation, Doug. Jim had developed Doug Funnie through doodles during a time of the early days of his career. Doug and his dog Porkchop first appeared in Jinkin's book Doug Got a New Pair of Shoes, which led to him creating an animated pilot titled Doug Can't Dance. He sold the Doug pilot to Nickelodeon. The pilot tested higher than any other pilot for the network at the time. Jinkins established Jumbo Pictures in 1990 to produce Doug for Nickelodeon. Doug went on to become one of Nickelodeon's most popular and successful series. Jinkins also created a TV show for Nick Jr, Allegra's Window.
Doug's success caught the eyes of Disney executives. In 1996 Jim sold Jumbo Pictures to Disney. Disney then developed Disney's Doug (originally Brand Spanking New! Doug) as part of their "One Saturday Morning" lineup.
Doug is not a powerful character. He is more where I feel that kids are today. They are softspoken and bewildered. But they often make the right decisions. What we tried to get across was that you should feel good about yourself and not give in to peer pressure. The underlying foundation was that doing the right thing will pay off.