Former navy submariner, businessman and political adviser, Rex Patrick has been approved to replace Nick Xenophon in the Senate.
Mr Patrick's nomination to fill the casual vacancy was endorsed by a joint sitting of the South Australian parliament on Tuesday.
He comes to the job after working as an advisor to Mr Xenophon for two years and plans to focus on areas such as defence, the manufacturing sector, energy prices and the Murray-Darling Basin.
Mr Xenophon quit the Senate recently to run for a seat in the South Australian lower house at the March state election.
Mr Patrick says he hopes to bring a range of experiences to his new role, with a focus on issues of importance to South Australia, including maximising local involvement in the future submarine and frigate projects.
"I will continue to put pressure on the government to make sure that we maximise Australian industry content in the submarine project and, indeed, the future frigate project," he said.
"I would hope that I can be a watchdog in terms of making sure that project is run effectively and efficiently as well."
He also plans to vote in favour of same-sex marriage, should the bill be brought before federal parliament.
During Tuesday's sitting, South Australian Premier Jay Weatherill said it was hoped Mr Patrick would be a strong advocate for the state's defence sector.
"Mr Patrick joins the Senate at a time of some turbulence and uncertainty in federal politics and at a time when the commonwealth government is considering making important decisions in relation to our future shipbuilding and submarine building industry," the premier said.
Mr Patrick will be sworn in on Wednesday.
