McDonald was placed in temporary charge following Justin Langer's shock resignation last month.
The 40-year-old oversaw Australia's first overseas Test series triumph in six years, Nathan Lyon taking 5-83 and Cummins 3-23 on the final day to secure a 115-run victory at Gaddafi Stadium.
McDonald is the favourite to land the role on a permanent basis and captain Cummins is full of praise for the former all-rounder.
Asked about the job McDonald has done, he said: "Fantastic. Not unexpected. He's a great operator.
"The boys absolutely love him. Very diligent, very thorough, strategic, very organised. He's a huge part of this tour win."
Cummins would clearly welcome a decision for McDonald to stay on.
The paceman added: "His preparation, and all the support staff's. It's not just the 11 players who walk out; we've got a squad of 30-odd people who have been working so hard this month, and it's also important.
"I've said before it's not my place to employ the coach, but Ronnie [McDonald] has been fantastic."
McDonald was unable to fly out with the rest of the touring party on Wednesday after returning a positive test on Tuesday.
Michael Di Venuto will coach the Twenty20 team in the absence of McDonald, who must spend a week in isolation.
A three-match T20 series gets under way in Colombo next Tuesday.
Sri Lanka and Australia will then play five ODIs this month before a two-match Test series in Galle.
Australia have not been in action since McDonald was appointed as Justin Langer's successor on a four-year deal.
McDonald, who has served as Australia's assistant coach since 2019, had been in interim charge of the side since Langer's resignation in February.
The 40-year-old four-time Test all-rounder had been expected to take over from Langer given his popularity among the playing group, who ultimately forced the former coach out.
McDonald took charge of Australia's recent 1-0 three-game Test series victory over Pakistan, while the side lost the ODI series 2-1 and won the sole T20 International.
Cricket Australia (CA) CEO Nick Hockley said that McDonald was the outstanding candidate.
"We interviewed several excellent candidates for this role, which is one of the most important in Australian sport," Hockley said.
"Andrew has already shown he is an outstanding Head Coach and the vision he outlined for the role during the appointment process was both impressive and exciting, making him our clear choice.
"We are proud of the way the team played and the respect shown throughout the tour of Pakistan under the leadership of Andrew, Pat and Aaron and really pleased Andrew is taking on the role permanently."
McDonald has experience in head coaching, having led Victoria and the Melbourne Renegades previously to all three domestic titles during the 2018-19 season. He has also coached sides in the Indian Premier League and English county cricket.
"I am honoured to be given this incredible opportunity for what is an exciting period ahead," McDonald said.
"The success of the World Cup, the Ashes Series and now Pakistan has been testament to the hard work and leadership of Justin, Pat and Aaron along with the players and the support staff.
"My plan is to build on the growth, depth and experience of the squad while working collectively with the group and across the game.
"There are many challenges in the short term which I know excites the leadership group, the players and the staff. I’d also like to thank my family for their support."
McDonald has been appointed across all three formats but CA noted he may step aside for some white-ball series given the workload of the role.
Australia are due to take on Sri Lanka in all formats in June and July, while they will defend their title on home soil at the T20 World Cup in October and November too.
Warner, 36, has just one Test century in the past three-and-a-half years – a cathartic 200 against South Africa during the 2022 Boxing Day Test in Melbourne.
Three cheap dismissals and a fractured elbow during the subsequent tour of India invited speculation that his 103-cap career could be coming to a close, with the likes of Usman Khawaja, Marcus Harris and Travis Head all options at the top of the order.
But he was named in Australia’s squad for next month’s World Test Championship final against India, as well as the first two Tests against England, and appears to have McDonald’s faith.
“We’re optimistic with what Dave’s got left,” McDonald told SEN Radio.
“We’ve picked him in the squad and we feel that he’s going to play a really significant part in the Ashes and the World Test Championship final.
“That’s why he’s on the plane. We think he’s got some good games left in him. He’s clearly in our plans.
“He knows exactly where he sits with us and internally we’re really settled around what we need to do and how we’re going to go about it.”
England bowler Stuart Broad said this week he was excited to renew his rivalry with the left-hander, having dismissed him seven times in 10 innings during a 2019 Ashes series that saw Warner average just 9.5.
McDonald prefers to focus on better days and is confident Warner can acquit himself well.
“In 2015, I think it was eight half-centuries and he averaged mid-40s. So, he’s had success there. It’s not as though he hasn’t had success in those conditions,” said McDonald.
“We’re backing him to draw on everything that he’s got. Leading into the Boxing Day Test the doomsday people were out there as well.”
Justin Langer guided Australia to a 4-0 Ashes thumping of England after lifting the T20 World Cup in December before rejecting a short-term contract extension with Cricket Australia (CA) in February.
CA's handling of the situation with Langer was widely scrutinised, with McDonald taking up an interim role to lead Australia to Pakistan for the first time since 1998.
Australia have fared well under his stewardship, claiming a 1-0 victory in the three-Test series and going 1-0 up in the three-match ODI series before falling to a 2-1 defeat, including a nine-wicket thrashing in the decider.
McDonald revealed he has held talks with the board about making his tenure permanent but is unwilling to commit to a definitive decision amid uncertainty surrounding the specifics of the role.
"Obviously the congested Test series didn't allow that but with a few more gaps in this one-day series I've had the opportunity to speak with Cricket Australia," McDonald said on Monday.
"Whether that becomes a follow-up conversation we'll wait and see. It will be pretty much like the other people who have no doubt spoken to Cricket Australia.
"Within the chats, there was no great detail or clarity on what the role would look like."
Pressed on whether he would like to take the job on a full-time basis, McDonald – whose influence has been praised by Test captain Pat Cummins – remained unsure.
"It depends on what it looks like, how Cricket Australia see the job unfolding and looking like and we'll get more detail on that going forward," he added.
"I don't really want to openly share what I think it should look like because that might put people in difficult situations throughout the process."
Australia conclude their tour of Pakistan with a one-off T20 on Tuesday and McDonald could have Josh Inglis and Ashton Agar to call upon after the pair recovered from COVID-19.
"[Agar and Inglis] returned their first negative test," he continued.
"They were in our last T20 set-up against Sri Lanka so depending on how they front for training, we will communicate with them on the possibility of playing."
The England and Wales Cricket Board (ECB) are in the process of recruiting separate head coaches for the Test and limited-overs teams after sacking Chris Silverwood.
Rob Key opted to move away from having one head coach to be in charge of every side following his recent appointment as managing director of England men's cricket.
McDonald was appointed as Australia head coach for all formats last month and he believes it is important to have just one boss.
Asked if there was any prospect of him going for a job with England, he told SEN: "No I don't think there was a risk.
"I think the way that they're going to set-up, structure up, is clear. I think they're going to go for a split coaching role. My views on that differ slightly.
"My belief is to still have that one coach and share the workload within that. I think for me the continuity of messaging is critical. But also the priorities shift. And people probably don't like me saying this, but the priorities do shift at certain times. You can't be everything to everyone.
"For example, Pat Cummins, on the back of three Test matches in Pakistan, at the end of that he's severely fatigued and then the white-ball team gets compromised because Pat Cummins isn't playing. But he's not ready to perform in that environment.
"If you had split coaches, which format takes priority? So, I think the ability to have one selection panel, one coach to work through that, give the direction to what the priorities are at the time and managing the overall squad as such and then someone, potentially a Michael Di Venuto or another assistant coach, coming in to allow the head coach to balance the workload but still stick on the same path.
"For example, we're going to build towards the 2023 World Cup, am I going to do every one-day game leading into that World Cup? There's no chance of that. So I think that the continuity of messaging for me is important."
