Mid North-based independent MP Geoff Brock will step back from the ministerial duties he holds with the SA Labor Government, making the announcement in Parliament.
He will stay on as Member for Stuart, saying he intends to contest the next election in 2026.
Mr Brock holds the portfolios of Regional Roads, Local Government and Veterans Affairs, with him relinquishing these as of Monday.
He also acted as a minister in the Weatherill Labor government, holding the Local Government and Regional Development portfolios.
"I have always believed in making the most of every opportunity that has come my way, and I've fought hard for the communities and regions I'm so passionate about," he said.
"Each one of the portfolios I have been entrusted with - local government, regional roads, and veterans affairs - matters to South Australians and shapes their everyday lives.
"But nearly a year after my heart attack, I recognise it's time to step back, in the best interests of my health, my family and my constituents."
Mr Brock said he intends to make his "sole focus" the electorate of Stuart and the local communities across the Upper Spencer Gulf.
"Port Pirie, Port Augusta and Whyalla have a once-in-a-generation opportunity to bring in a new era of economic prosperity for our state," he said.
"It will be my job to make sure this opportunity is seized for this generation, and the next."
Mr Brock said he was proud of the initiatives he had implemented in the past two years as minister, including undertaking a review of local government elections, with a goal to get better representation for local communities.
"The ideas that have flowed during the public engagement and consultation process have been pleasing and creative - giving me reassurance that councils are important to the community," he said.
As Minister for Regional Roads, he said he had been "determined" to drive along as many of the 18,000 kilometres of state-maintained sealed roads as possible, as well as onto some of the 9400km of unsealed roads.
"I've spoken with all kinds of travellers, far and wide, and they're always keen to tell me about the roads they've travelled," he said.
"When it comes to outback roads, I've come to understand the importance of local knowledge.
"I was very pleased to establish the Outback Roads Consultative Form, with its inaugural meeting next month, co-convened by the Department for Infrastructure and Transport and the Outback Communities Authority."
Premier Peter Malinauskas said Mr Brock had "served with distinction" and "provided a strong, independent, regional voice".
"I'm grateful that Geoff agreed to stay on in Cabinet through the recent significant Major Economic Summit in the Upper Spencer Gulf," he said.
Mr Malinauskas said he would announce a subsequent reshuffle of Cabinet duties in due time.
