Court documents filed in St. Paul, Minn., stated Mike Allen entered the plea Monday to a misdemeanour offence.
The documents show the Fort McMurray-Wood Buffalo member of the legislature was fined $500 and must pay an additional $500 in court surcharges and fees.
He must also serve one year probation.
He was originally charged with a more serious gross misdemeanour offence.
In a statement issued Wednesday, Allen stated he considers the matter closed.
"I am relieved to have this matter behind me and will make no further comment at this time," said Allen in the statement.
"I accept full responsibility for my behaviour and regret any embarrassment I caused.
"As a result of my actions I expect to be held to a higher standard, and I can now focus on continuing to work and advocate for issues in my community."
Allen, a rookie MLA, was turfed from Premier Alison Redford's Progressive Conservative caucus after he was charged in July. He is currently sitting with the opposition as an independent.
The 51-year-old was arrested while in Minnesota representing the province at a conference on cross-border issues.
Officers there had posted a fake ad on an online site for escorts and massage services called backpage.com.
Police reported Allen responded to the ad over the Internet and information was exchanged through cellphone texts about when and where he would meet two female undercover officers.
Allen met the pair and agreed to pay about $200 for sex with two women. He then began to undress when other officers entered the room and arrested him.
He has since told the Fort McMurray Today newspaper he ended a serious relationship prior to the St. Paul trip and was lonely.
Allen is single with grown adult children.
The Opposition Wildrose party called for Allen to resign as soon as he was charged, saying he couldn't function as a public representative while facing criminal charges.
The NDP has said Allen should resign if convicted.
Redford's office declined comment Wednesday.
After his arrest in the summer, Redford told reporters she was "disgusted" by Allen's actions.
"You'll know that in Alberta when I was justice minister, we started doing work with respect to the sexual exploitation of women and human trafficking. This is an issue that is very close to my heart," Redford said at the time.
"I was shocked and disappointed to see the conduct. It's not at all the standard of conduct I would expect from anyone in our caucus."
Redford said she demanded that Allen reimburse the government for all the expenses he incurred on the trip and said later he had done so.
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