In 1871 Bent was elected to the Victorian Legislative Assembly for the district of Brighton, defeating the veteran liberal George Higinbotham "to the amazement of every one". He had no particular party loyalties and first held office in the Service government in 1880. He was Commissioner for Works and Railways in Sir Bryan O'Loghlen's government in 1881–1883, and used this position to extend the railway line from Caulfield to Cheltenham, thus enormously increasing the value of his own property developments. His lifelong reputation for corruption dates from this period. The exposure of Bent's dealings led to the defeat of O'Loghlen's government at the 1883 elections.