Dave Wilson was sentenced in April after admitting to defrauding the public purse of nearly $61,000.
Justice Department spokeswoman Tara Walsh says Wilson was released from custody Wednesday.
Wilson, who also received 18 months' probation, pleaded guilty nearly a year ago to fraud, breach of trust and uttering forged documents.
The former Liberal was one of four politicians charged in the province's constituency expense scandal.
Richard Hurlburt, a former Progressive Conservative cabinet minister, was sentenced to a year of house arrest in July after pleading guilty to charges of fraud and breach of trust.
Russell MacKinnon, a former Liberal cabinet minister, has pleaded not guilty to fraud, breach of trust and uttering forged documents. His trial is set to begin in March.
Independent member Trevor Zinck, who is charged with fraud over $5,000, breach of trust and theft over $5,000, has yet to enter a plea. His case has been adjourned until September.