Rannowane obtained a Bachelor of Laws from the University of Botswana in 1990, and he obtained a Master of Laws from the University of Warwick in 2003.
[1] He began his career as a Magistrate Grade II in 1990.
He was appointed Chairman of the Botswana National Parole Board in 2004 and held the position until 2018.
In 2012, Rannowane chaired the National Delimitation Commission to draw the parliamentary constituencies of Botswana.
[2] In 2018, President Mokgweetsi Masisi appointed Rannowane as the Chief Justice of Botswana.