Mr Ross, who was a vocal critic of the PM’s predecessor Boris Johnson during his time in Number 10, was asked if he still has faith in Ms Truss – who is already facing questions over her leadership a month after taking on the top job.
He responded “Yes I do” – adding the Tories can “absolutely” win the next election with her in charge.
Mr Ross also insisted that new Chancellor Kwasi Kwarteng could stay in post, despite the financial turmoil sparked by his mini-budget.
Speaking on BBC Radio Scotland’s Good Morning Scotland programme, he said the Chancellor had “listened to the public, he has listened to the response from the markets” by reversing plans to abolish the top rate of tax for high earners south of the border.
Looking to the future, Mr Ross conceded: “There will be difficult challenges and decisions to be taken going forward.
“But there are also great opportunities for our great country and I want to see them realised.
“These are really challenging times, for the Government here in the United Kingdom and indeed governments across the whole world, we are dealing with a global cost-of-living crisis.”
He stressed the Tories need to “be united” and deal with the big issues.
Mr Ross said: “There’s clearly major issues facing the country, we see that for many governments across the world right now, these are extremely difficult times.
“But we need to get together, to be united, and to tackle these issues on behalf of local people, communities and businesses who are really struggling.”
“I want that focus to be on helping those individuals, families and businesses going forward.”
His comments came as he insisted action to help people with soaring energy bills had been a “crucial” part of the Chancellor’s controversial mini-budget.
“The Government looked to help people who were really struggling,” Mr Ross said.
“They were facing energy bills that were undeliverable, they couldn’t afford their energy bills.
“They are still very high but the Government have been able to step in and help families.”
Mr Ross also said the UK Government should increase benefits – but refused to go as far as saying that payments should rise in line with inflation.
“I think there should be rises in benefits for those who are struggling the most and I think we will see that from this Conservative Government,” he said.
“The Conservatives have always, and I know will continue to, support those who need the most support.
“So yes, I think they should get the most support they can get from this Government.”