John Thomas Harris (May 8, 1823 – October 14, 1899) was a nineteenth-century politician, lawyer and judge from Virginia. He often referred to after the American Civil War as "Judge Harris", even after his election to Congress. He was the first cousin of John Hill.
John Harris was a lawyer before he became a politician. 
The sentence reads "was a nineteenth-century politician, lawyer and judge from Virginia". It places politician first among his career achievements in the description but it's not meant to be a timeline.  Politician was the last thing on that list that he did so he was a lawyer before holding political office and becoming a politician. 