Greg comes from a racing family. His father, George, trained in Louisiana, Michigan and Chicago. He began working for his father as a child, walking horses as early as age 8. He went out on his own in the early 1980s and scored his first winner with Admiral's Command. He was assistant to trainer Gene Cilio for nearly 10 years and took over upon Cilio's death in Nov. 2003. He won his first stakes race with Out of My Way in the Taylor's Special Handicap at the Fair Grounds in Feb. 2004, and captured his first
graded stakes with Allspice in the Grade III Sixty Sails Handicap at Hawthorne that April. In 2004, Geier's first full year on his own, he had 14 winners at Arlington. Won the Grade III Hanshin Cup with Coragil Cat in 2008.