In the House of Assembly he soon made his mark and became Attorney-General in John Cox Bray's cabinet on 24 June 1881. He endeavoured to bring in several law reforms, and though his married women's property bill was not passed, he succeeded in carrying bills allowing accused persons to give evidence on oath, and amending the insolvency and marriage acts. The government was defeated in June 1884, but a year later, on 16 June 1885, Downer himself became Premier for the first time, as well as being Attorney-General once again.