On his fifth attempt, Roberts earned his PGA Tour card at the PGA Tour Qualification Tournament in 1980 for the 1981 season. He returned to the tournament in 1981, 1982, 1986 and 1987, earning his card every year except 1981. He did not get his first win on the PGA Tour until 1994 at age 38, yet it sparked a nine-season run of eight victories. His career earnings are over $15 million. He is known as "Boss of the Moss" for his putting skills. He has featured in the top 20 of the Official World Golf Rankings.