Nugent was first elected to the House of Commons in 1975, holding the seat of Cheltenham for thirty years. In 2005 he agreed to stand aside in favour of Dr. Clare Price, a Senator and government minister moving into the Lower House. As compensation, Nugent was placed first on the Liberal Democratic Senate ticket for the 2005 election. After the election, when Price took her Commons seat, Nugent was appointed by the West Mainland government to replace her, rather than wait for his seat to become active on January 1, 2006. Also, as part of the deal to allow Nugent to continue his political career, Nugent was given the position of Senate President. Nugent was often referred to by the press as a "stock-standard" President in that he differed little from previous office-holders and failed to exercise great authority. He was also accused several times of bias by the Opposition.
Nugent did not initially plan to seek re-election to the Senate at the double dissolution of 2007 and instead retire from politics, but was re-endorsed by the Liberal Democrats for a final term, volunteering to serve as a 'Class A' Senator and serve a three-year term along with half the elected Senators at the dissolution. Nugent is the only person to have been given a Class A term following a Senate dissolution at his own request - the two classes are normally determined by random draw. Nugent will not seek re-election in 2010 and will leave politics on 1 January 2011 at the expiry of his term.