Hislop was first elected for the
Waitaki electorate in the
1876 general election, and was re-elected in
1879. He resigned on 28 April 1880 "for private reasons". He then represented
Oamaru from an
1885 by-election to 1889, when he resigned from his two ministerial portfolios (effective 10 September 1889) and his parliamentary seat (effective 4 September 1889) over the Ward–Hislop Affair. He won the resulting
1889 by-election, but was defeated by
Thomas Young Duncan at the next general election in
1890. He contested the
1896 general election in the
Wellington Suburbs electorate, but was defeated by
Thomas Wilford, with 2194 to 1942 votes. An election petition was filed one month after the election, accusing Wilford of bribery, illegal practices and not being properly registered as a voter himself. It was argued that only Hislop was properly registered, and should thus be returned. Wilford's election was declared invalid, but a by-election was called. Hislop declared that he would not stand in the by-election in favour of the opposition candidate
Arthur Atkinson, who had come forth in the three-member
Wellington electorate.
Charles Wilson from the
Liberal Party narrowly defeated Atkinson in the
1897 by-election. Hislop was a member of the
Atkinson Ministry from 1887 to 1891, holding posts as
Colonial Secretary and
Minister of Education. The education portfolio filled Hislop with great pleasure, as he was thus following in his father's footsteps, as he had been the author of the Education Act. Hislop drafted the Fair Rent Bill, which was introduced by the
fifth Atkinson Ministry, and passed through the Lower House. He also introduced labour bills, factory and shop hours, and employers' liability bills, also building liens and the Truck Act, which, however, were not passed. He was successful in passing the Shipping and Seamen's Act. He also effected some useful legal reforms, and introduced the Representation Bill, a measure based on the
Hare system, but this was withdrawn. Hislop's political views were on the left of the spectrum. As a minister, he was involved in the
1889 Paris Exposition. For that, and for his services to education in general, he was honoured by the French Government with a
Legion of Honour award. He contested the
Newtown electorate in the and elections. In 1902, the electorate was contested by
William Henry Peter Barber, Hislop,
Charles Luke,
William Chapple and William George Tustin. They received 1385, 1357, 1100, 1017 and 159 votes, respectively. The 1905 election was contested by William Henry Peter Barber, Hislop, William Chapple and
Alfred Hindmarsh. They received 3231, 2018, 1795 and 383 votes, respectively. Hislop was Mayor of Wellington from
1905 to 1908. Hiropi Street in Newtown is named after Hislop. He was a Member of the
Legislative Council from 1921 until his death. ==Family and death==