Henneman was born in Cape Cross in 1959 to doctor Luis Ramirez (Spanish) and Eila Menon (Indian). Graduating from high school in Cape Cross with top honours (97% average), Henneman would go on to study political science at the London School of Economics from 1978-1982. Upon returning to Brunant, she worked in Congress and later joined the Social Democratic Party.
She ran for the presidency twice, first in 1990 and 1996, becoming the first non-white to become president. Henneman became a very active president, involved in government activity and often challenging Congress in matters she thought were not in the public's best interest or less supported.
She married the future President and Prince of Roseland Gert Henneman in 1987. They have two children, Henrik (born 1989) and Annelise (born 1992). She and Gert divorced in 2011 over an affair he had.