Truss was born in the region of Kingaroy, Queensland. He attended a small state school and was a bean farmer before he entered politics. He was chair of the Sugar Coast Burnett Regional Tourism Board and a councillor of the Shire of Kingaroy 1976–90. He was Chairman of Kingaroy Shire Council from 1983 to 1990.
In June 2005John Anderson announced his intention to resign as National Party Leader. Deputy Leader Mark Vaile was elected the new Leader, and Truss was elected Deputy Leader. In the reshuffled ministry following Anderson's resignation Truss became Minister for Transport and Regional Services. In 2006, following the AWB oil for food scandal, Truss and Vaile swapped portfolios, with Truss becoming Minister for Trade and Vaile taking the Transport and Regional Services portfolio until the defeat of the Liberal/National Coalition government at the 2007 election. After the election, Mark Vaile resigned as National Party Leader, citing the party's need for "generational renewal". With some reluctance, Truss nominated for the leadership, and was elected as federal leader of the Nationals on 3 December 2007. In 2008, Coalition leader Malcolm Turnbull appointed Truss as Shadow Minister for Trade, Transport, Regional Development and Local Government. He retained that portfolio after Tony Abbott became Coalition leader in late 2009. Following the 2010 election, Truss became Shadow Minister for Infrastructure and Transport. At this election, Truss was elected for the Liberal National Party, which had been formed from the 2009 merger of the two non-Labor parties' Queensland branches. However, he continued to sit as a National, and remained the Nationals' federal leader.
Truss retained his seat in the 2013 Federal election, in which the Coalition was elected to a strong majority government. On 18 September, Truss was sworn in as Deputy Prime Minister, per a longstanding agreement between the Liberals and Nationals. The leader of the Nationals has ranked second in all but two non-Labor governments since the Coalition was first formed in 1923. Truss remained Deputy Prime Minister after Turnbull deposed Abbott in a 2015 leadership spill. On 11 February 2016 Truss announced his decision to retire from politics at the 2016 federal election and immediately resigned as Nationals leader and Deputy Prime Minister. Barnaby Joyce was elected as leader and was sworn as the Deputy Prime Minister. Truss also resigned from cabinet and returned to the backbench. Truss's leadership of the Nationals was considered steady, albeit rarely visible. Despite being the number-two man in the government, Truss was relatively unknown; only one in five Australians were familiar with him. He lifted the party's representation in the House of Representatives from ten seats in 2007 to 15 seats in 2013.
In the American television seriesLost, Warren Truss was briefly referenced as having been assaulted in a bar fight by main character James "Sawyer" Ford, though the conflict and Truss himself are never onscreen.