A former Adelaide real estate agent who used his position as a trusted pastor to steal $3 million from friends and the church community has been jailed over what a judge described as a cruel and callous scam.

David Owen Parkinson, 63, pleaded guilty to more than 50 theft and deception offences committed over a four-year period between 2009 and 2013.

Parkinson worked at the Ray White real estate agency in North Adelaide and tricked his victims into paying him hundreds of thousands of dollars, the District Court heard.

He claimed clients would profit from real estate investments both in South Australia and overseas.

The court was also told he met many of his victims through his role as an associate pastor at an Adelaide church.

In handing down his sentence, Judge Jack Costello said Parkinson had affected the lives of many people in a "calculated and devious" scheme motivated by personal gain.

"You cruelly and callously duped innocent people into departing with money, sometimes saved, sometimes borrowed to either enable you to continue to support your lifestyle or to help you to maintain the appearance of legitimacy of business ventures which were nothing short of deceitful scams," he said.

"You consciously used and abused the trust and respect of people who otherwise trusted you as their assistant pastor in order to lure them into giving you money that they understandably expected would be wisely invested.

"You breached that trust and stole not just their money but in many instances their ability to properly enjoy their lives."

The court heard Parkinson had used some of his profits to live an extravagant lifestyle which included the purchase of a $114,000 Mercedes.

The funds were also used to employ a personal trainer, dine out at North Adelaide restaurants and to purchase thousands of dollars worth of tailored suits.

The court heard Parkinson told one of his victims that some of his investment was going towards helping children in Africa.

"I regard this act of dishonesty as particularly callous," Judge Costello said.

"You sought to exploit his Christian ethics and sense of decency to your own illegal and greedy ends."

Parkinson used 'gift of the gab' to dupe victims

Judge Costello said Parkinson's offending was too serious to suspend the jail sentence or to allow him to serve it on home detention.

He imposed a head sentence of seven years and eight months in jail, and a non-parole period of four years and four months, which was backdated to when Parkinson was taken into custody in July 2015.

The court heard while some of the money had been paid back to the victims, more than $1.5 million remains outstanding.

Outside court, victim Jim Gerazounis welcomed the sentence.

"I think it is a good outcome. All the folks can have a bit of a rest now, relax and move on with their lives," he said.

He said he had lost close to $200,000 to Parkinson's schemes and is yet to see a dollar returned.

"It was pretty ruthless to deceive so many people," he said.

"It's hard to trust people now if it's do with real estate or money. You think twice or three times and even then you're not sure."

Victim Bob Charles said he was relieved Parkinson was not permitted to serve his sentence on home detention.

"I think he got his just desserts there," he said.

He said Parkinson used his "gift of the gab" to deceive innocent people.

"He was a very good speaker and very plausible," he said.

"He used his position as a pastor to draw people in and it unfortunately then reflects badly on all good church going people who don't do this."

Parkinson, who appeared in court via video link from the Mount Gambier prison, showed no emotion as the sentence was handed down.