He was a senior minister in the O'Farrell, Baird, Berejiklian and Perrottet governments, serving in various portfolios including Planning, Resources and Energy.

[5][6] After Roberts was elected to parliament in 2003, Flagship Communications acted on behalf of owners of the Orange Grove site.

[7] Then NSW Premier Bob Carr claimed in 2004 that, "there appeared to be a warm relationship between Gazcorp and Mr Roberts, evidenced by a stream of faxes and emails giving the Liberal MP questions to ask of the Labor Party about the factory outlet".

[9] Roberts left Howard's office when he was elected as the Member for Lane Cove in 2003, following the retirement of Kerry Chikarovski.

On 3 April 2011, subsequent to the state election, Roberts was appointed as the Minister for Fair Trading in the O'Farrell government.

[1][14] Following the 2015 state election, Roberts was sworn in as the Minister for Industry, Resources and Energy, and retained his role as Leader of the House.