A former senior adviser to Stephen Harper says the prime minister knew about criminal charges he'd faced, despite Harper's assertion that he would never have hired Bruce Carson had he known about "more recent things."

Carson, who has written a book about his time in the Prime Minister's Office, worked closely with Harper and his then chief of staff Ian Brodie from 2006 to early 2009. The book, 14 Days: Making the Conservative Movement in Canada, talks about the early days of the Harper government.

"I disclosed it on the form that I had to fill in, he and I had a general conversation about my past and I disclosed it fully to Ian," Carson said in an interview with Evan Solomon, host of CBC News Network's Power & Politics.

Carson went from a well-liked backroom adviser to headline news during the 2011 federal election when an APTN news story alleged he lobbied officials at the Department of Indian and Northern Affairs Canada about a water purification system.

Reporters soon discovered Carson had a history of financial problems and was convicted of five counts of fraud going back to the 1980s and 1990s before he was hired as an adviser to Harper.

In June 1990, Carson pleaded guilty to three counts of fraud and received a suspended sentence and 24 months probation on condition that he "continue treatment at the R.O.H. (Royal Ottawa Hospital)" and make restitution of $4,000 within 23 months to the car rental company he defrauded. He later declared bankruptcy, which his lawyer said in 2011 was the result of Carson being out of work and juggling two families.

Harper said at the time that he didn't know the extent of Carson's criminal record.

'3rd chance'

"We knew about problems in Mr. Carson's very distant past. We didn't know about more recent things. If I had known that we would not have hired him. I am obviously very disappointed to find out these things now," Harper said in April 2011.

Carson has since been charged with illegal lobbying and influence peddling. His pre-trial on the counts stemming from the water purification work starts Monday, with other charges laid earlier this month

Carson says he did "as good a job as one can do" when he was with the Prime Minister's Office.

Some people, he said, are of the opinion that "everybody's entitled to a second and perhaps a third chance. And when I worked for the prime minister in opposition and in government, my past was known to him [Harper] and certainly to Ian Brodie, and I thought we accomplished really good things."

"Regardless of the negative stuff, nobody's attacked what I've been able to do or the kind of work I did as an adviser either to Ian or to the prime minister," Carson said.

"The time I spent with him, it was the best job I ever had, and I really enjoyed it."

Senate, Supreme Court scandals wouldn't have happened

Carson says the Senate scandal wouldn't have happened under him and Brodie.

"Certainly not the way it happened. Neither Ian nor I would have been able to dig 90,000 bucks out of our pockets," Carson said.

Nigel Wright, who was Harper's chief of staff until last May, left the PMO after a news report revealed he'd personally given Senator Mike Duffy $90,000 to repay Duffy's questionable Senate living and travel expenses. Harper has maintained he didn't know about Wright's plan, which emails suggest was discussed with several PMO staffers.

Brodie and Carson also discussed everything with Harper, Carson said.

"Things were different," he said, but, "if [Harper] said he didn't know, I think you have to believe him."

Carson says it's unfortunate Harper is in the midst of a spat with Beverley McLachlin, the chief justice of the Supreme Court, after accusing her of trying to interfere with one of his appointments to the top court.

"I think if I'd been here, if Brodie had been here ... no one would have advised him to take on the chief justice of Canada on anything, especially in a public way. The problem is, as more and more digging is done into the back and forth on the [Marc] Nadon appointment, it just becomes worse and worse," Carson said.

"It's certainly not a fight a prime minister should be picking."

Carson also notes in the book that Doug Finley, who ran the 2006 campaign, said he had a mole in the federal Liberal election campaign who gave the Conservatives the Liberal platform. Finley died a year ago.

Carson says he has no idea who the mole was.

With files from the Canadian Press