In February 1846 Knight was appointed as the country's inaugural auditor-general and in 1855 became manager of the Colonial Bank of Issue and then auditor of public accounts and chaired many official commissions into subjects as diverse as flax production, meteorology and civil servant employment conditions.
In New Zealand, Knight first lived in Auckland and when the government moved to Wellington, he also relocated to the new capital in 1865.
Knight exchanged letters with Joseph Hooker Director of the Royal Botanic Garden at Kew for over 30 years.
[3] During 1868 and 1869 Knight was in Britain with Grey, and was able to spend time with the botanists and lichen collections at Kew.
[2] Knight's extensive personal collection of specimens is in Museum of New Zealand Te Papa Tongarewa although he also contributed to around 20 other herbaria in other countries.