Dunham began performing for audiences as a teenager, in various venues such as school, church, and during his job at Six Flags. By his middle school years, he began to perform for banquets attended by local celebrities such as Dallas Cowboys quarterback Roger Staubach, having developed his style of lampooning those he performed for, using the puppets to say things too risque for him to say without them. Dunham's television debut came in 1976 when the still prepubescent performer caught the attention of Dallas reporters like Bill O'Reilly, who interviewed Dunham for a local news story. Dunham later did commercials for Datsun dealerships in Dallas and Tyler while still in high school. While emceeing a high school talent show, he dealt with a heckler, and won over the rest of the audience. During this period he became so associated with his craft that he and one of his dummies "cowrote" a column in the school paper, and he would pose with his dummies for yearbooks as an inexpensive way to acquire professional photos of his act for promotional purposes. He was voted Most Likely to Succeed, and in 1980, after he graduated from high school, Dunham gave himself a career goal of obtaining, within ten years, an appearance on "The Tonight Show Starring Johnny Carson", which was seen as the "holy grail" for comedians.