Alex Neil said policy making became more centralised within the Scottish Government after Alex Salmond stepped down as First Minister in 2014 following the referendum on independence.
The MSP for Airdrie and Shotts said Ms Sturgeon’s creation of a policy unit headed by civil servants rather than politicians was “a big mistake”.
Mr Neil served as health secretary under Mr Salmond but was switched to a wide-ranging social justice brief when Sturgeon became First Minister.
In an interview with the Institute for Government to mark 20 years of devolution, he said: “With Alex Salmond, I think he let you get on with the job. Nicola interfered much more, and policy making was centralised in her office. Sometimes they weren’t even involving the responsible minister, in my view.
“She’s created a policy unit that’s only civil servants, and I think that’s been a huge mistake.
“The head of the policy unit, I’m not saying they should be an MSP or a practising elected politician, but it’s somebody who should know about the politics of the Government, the Government’s party, and also more generally.
“I don’t think you make good policy if you leave it up to civil servants. Civil servants, on their own, are not good at devising policies.
“A policy unit, yes, that’s the right thing to do, but you have to have a political team at the top of it. You still need civil servants, because they do stuff. They have input to bring to the party, because they know how the machinery works and all the rest of it. They’re good at research and stuff like that.
“But, I think that’s been a failing, the fact that the policy unit is just civil servants. I think some bad decisions have resulted from that.”
Mr Neil added that he regretted not being able to reform the NHS in Scotland as much as he would have liked when serving as health secretary.
“I loved the health job,” he continued. “It was 24/7 and I just wish I had longer. I wanted to make some big changes, but unfortunately those changes haven’t been made, and that’s one of the reasons why I think the new health secretary (Jeane Freeman) is facing some of the challenges that she is.”
Mr Neil also recalled his dealings with UK Government ministers. He described Philip Hammond, the then transport secretary, as being an “arrogant sod” who “simply wasn’t interested in Scotland”.