Nanson was a minister in the governments of Alf Morgans, Walter James, Newton Moore, and Frank Wilson, including as attorney-general from 1909 to 1911.

[2] In November 1901, after only seven months as an MP, he was made Minister for Lands in the newly formed Morgans ministry, which lasted for just 32 days.

He replaced Hector Rason as Minister for Works a few months later, but the government fell in August 1904 (after a vote of no confidence).

He retained his portfolios when Frank Wilson replaced Newton Moore as premier in September 1910, but the government was defeated at the 1911 election.

Janet Nanson wrote under the nom de plume of "Sigma" in Perth and when she worked for the Western Mail as the founding writer of "Aunt Mary".