Whilst still at college, Pennington began working in the family retail feed and seed store founded in Madison, Georgia in 1945 on Main Street by his father, Brooks Pennington Senior Over the course of 50 years, he built a warehouse and developed the wholesale side of the business and also developed new agricultural crop varieties, seed coatings and seed treatments.
He attended North Georgia College in 1943-1944, before serving as a United States Air Force captain in the Korean War, and later graduated from University of Georgia with degrees in engineering and agronomy.
He retired as President and Chairman of Incorporated. due to ill health in the mid-1990s., the annual turn-over had grown to over $200 million. Pennington was also served as president of the Georgia Seedsmen"s Association, the Southern Seedsmen"s Association, and the Southern Field Seed Council. His book Seeds and Planting in the South is regarded as a standard text-book for many agricultural colleges.
In September 2003, Pennington was entered posthumously into the Georgia Agricultural Hall of Fame.
He was also State Campaign Chairman for President Jimmy Carter"s first campaign for governor of Georgia in 1966 (unsuccessful), and later an agricultural campaign advisor during Carter"s 1976 presidential campaign. Pennington donated his political pay to the Brooks Pennington Senior
Scholarship Fund (named after his father), which by September 2003, had enabled over 30 students to attend college. He served as the chairman of the Morgan County Hospital Authority, vice chairman of Morgan County Foundation, president of the Morgan County Touchdown Club, and was the Commander of the Morgan County, Georgia Veterans of Foreign Wars, among other positions.
After his death, his estate endowed the Brooks Pennington Junior.
Military Leadership Center at North Georgia College & State University (NGCSU) in November 2004.
Pennington served as a member of the Georgia House of Representatives and was elected to the Georgia State Senate, serving for eight years as Chairman of the Georgia Senate Agriculture and Natural Resources Committee, as well as holding positions on a number of other committees.
