Answer
The last public office that Henry Parkes held was Premier of NSW. Parkes was a member of the New South Wales Legislative Assembly from 1854 to 1891, and served as Premier on four occasions: 1872-1875, 1875-1877, 1877-1883, and 1887-1889. He is best known for his role in the Federation of Australia, and was one of the signatories of the Australian Constitution.