[2] He was then moved to west Africa, serving successively as Secretary and Acting High Commissioner of Southern Nigeria (1901-1904) and governor of Sierra Leone (1904-1910).

During his six years as governor of Sierra Leone (1904 to 1910) he held referendums with the indigenous population to judge whether or not there was popular support for proposed policies.

When he was replaced by Edward Merewether, many Africans who worked for the British government in Sierra Leone petitioned that they "wanted Probyn back.

However, Probyn mandated that this be subject to "safe and rigid qualifications", meaning that the majority of black Jamaican women were still effectively denied the right to vote.

Probyn was also the author of a number of treatises on legal practice, and was a regular contributor to the literary magazine The Nineteenth Century and After.