"He ran afoul of one of the rules down there," Lombardo added, saying he could not be more specific.
Attempts to reach Harrison were unsuccessful.
He was hired by the borough in early 2013, after a lengthy search launched after longtime Chief Glenn Scheetz retired in 2011.
Wenonah officials did not say what Harrison, a 20-year veteran of the New York Police Department, needed to accomplish at the academy. A notice on the borough's website, posted in early January, said he would return in May upon completing the courses. The training was directed by the Police Training Commission, under the state Attorney General's Office.
A spokesman for the office said Thursday that he was unable to provide information from the commission on the issue.
Lombardo said Harrison addressed the council prior to the decision last week, during an executive session. "He appeared and he explained his side of it," he added. "We were left with no choice."
Minutes of the executive session were unavailable.
Noted Lombardo: "He's a good guy. He did a good job. People really seemed to like him."
Speaking to the South Jersey Times after he was hired, Harrison said the job was "more pleasant" because "there's an intricate involvement and relationship between people and the officers that you can't find in city policing."
Council President John Dominy, who oversees public safety, would not discuss the decision Thursday, except to say, "He's no longer employed by the borough."
Mitchell Sklar, executive director of the New Jersey State Association of Chiefs of Police, said in an e-mail that chiefs must be sworn and certified in the state.
"In order to be a sworn officer, you must attend a New Jersey police academy and complete the required course," he said. "In this instance, it is my understanding that he did not complete the required course, so, according to New Jersey law, he could not serve as a chief of police."
Harrison's salary was about $100,000, according to Lombardo. Sgt. William Rogers will oversee the department until a search identifies a new leader for the six-officer force, Lombardo said.
The borough of nearly 2,300 recorded no violent crime in 2012 and 2013, according to state police records. Last year, there were fewer than 30 nonviolent incidents, mostly thefts.
Given the borough's size and budgetary constraints, policing has been eyed as a potential service to share with neighboring towns. The proposal was last considered in 2011 and rejected through a nonbinding referendum.
In January, shortly after the announcement of Harrison's temporary absence, an item on a Jan. 23 council draft agenda listed "discussion on possible disbanding police dept."
Dominy, who acknowledged "pressure to merge coming down from the state," maintained in January that there was no such discussion planned, contending the item had been listed by mistake.
Lombardo, who advocated for the move in 2011, said he did not know of any political will to revive the proposal.