Both the province and the guard's union, the Alberta Union of Provincial Employees, confirmed the dismissal Tuesday.
The guard, who was not named, was one of four let go. All worked at the Fort Saskatchewan Correctional Centre.
"They were supervisors who abandoned their posts and in doing so posed a significant risk to the public, inmates and especially to their colleagues," said Dan Laville, spokesman for the Solicitor General's Department.
"These staff members were all leaving the correctional centre virtually unmanned."
Three other guards were fired over the summer, while the fourth had just recently returned to work after being on leave.
Laville said there are no more investigations on the actions of corrections staff arising from the strike.
The four were part of job action that flared up in other jails when two guards at the new $580-million Edmonton Remand Centre were suspended on April 26 after voicing concerns about safety at the facility.
Their colleagues set up a picket line and refused to report for work, saying the workers had been disciplined unfairly.
The anger and job action spread to other remand centres and eventually to provincial sheriffs, who provide security at courthouses, and other court staff.
The strike was ugly, costly, and brought short-term chaos to the justice system. An agreement was reached to end it only after the courts got involved and began levying crippling fines for defying back-to-work orders.
AUPE was fined $350,000, but went back to work before the penalty reached $500,000, saying it had reached a deal with the province to investigate the safety issue.
On Tuesday, AUPE president Guy Smith said they are grieving the four dismissals and have asked for expedited arbitration.
“We will continue to stand by our members and fight this needless discipline,” said Smith in a news release.
Smith said the government promised not to seek any retribution against members who participated in the wildcat strikes as part of the deal to end the impasse.
“Several senior officials, including Premier Redford, made that promise publicly,” said Smith.
“They’ve gone back on their word and are trying to make an example of (the four guards) to intimidate every corrections worker in the province.”
Laville, however, said that while the government has no intention of being punitive, no blanket amnesty was ever offered.
He pointed to a letter sent by Alberta's Public Service Commissioner to the AUPE at the time.
"With respect to your request for amnesty for striking employees, it is not our intention to seek retribution, and following a return to work we will consider all circumstances on a case-by-case basis, and act thoughtfully and in a measured and appropriate fashion," Public Service Commissioner Dwight Dibben wrote on April. 30.
The opposition Liberals and NDP have said the walkout was the last resort for a group of workers left with no other option to have their concerns listened to by Premier Alison Redford's government.
Also on HuffPost