At the age of 13 Hornibrook commenced apprenticeship with builder HW Fooks. In 1912, at the age of 19, Manuel with his brother Reginald established their own business which started with building drainage channels and sewerage systems. Soon the bridge building became Hornibrook’s speciality.
The business quickly moved into civil engineering contracting, excavating the State’s first open cut coal mine at Blair Athol in 1923. The William Jolly bridge built from 1930-1932 became his all-time favourite project because of the aesthetic appeal of the bridge and the pioneering use of the sand island method of pier construction.
Sir Manuel Hornibrook was the Chief Engineer during construction of the Hornibrook Bridge which was named after him.
He was the first Australian to be honoured with an honorary membership of the British Chartered Institute of Building.