Heidi Hartmann played her first professional fight on March 15, 1999 and won over four rounds on points. Against the strong Dutch Marischa Sjauw, Heidi Hartmann won the WIBF world welterweight title in 2004. The middleweight title followed in 2005 and the junior middleweight title in 2006, which she lost in 2007 to Karolina Łukasik from Poland .