Height: 6 ft 0 in (1.83 m)
Weight: 200 lb (91 kg; 14 st)
Birthdate: July 16, 1968
College: Oakland Community College
Year turned pro: 1990
Birthplace: Pontiac, Michigan, USA
Gillis was born in Pontiac, Michigan, in 1968. He attended high school at Lake Orion High School in Lake Orion, Michigan. After graduating from high school he went on to study at Oakland Community College where he played collegiate golf.
Gillis turned professional in 1990 and started his career playing on the Nationwide Tour, before finally progressing to the PGA Tour in 2010, although he had previously played some events on the PGA Tour during the 1990s. Gillis made the progression after achieving his first win on the Nationwide Tour, at the 2009 Nationwide Tour Players Cup. This win helped him to finish in 5th place on the end of season money list, earning him his PGA Tour card. Gillis also played on the European Tour between 1998 and 2002. Over his golfing career, Gillis has played in 26 countries worldwide.
After qualifying to play on the PGA Tour in 2010, Gillis retained his playing rights for 2011but then went on to lose them for the following season. After having a strong season playing on the Web.com Tour in 2014, Gillis again earned his PGA Tour card which qualified him to play on the Tour for 2015.
As of the end of 2014, had yet to achieve a win on the PGA Tour but had amassed total prize money of $5,501,412.