Dany Bernatchez has died in custody at the Atlantic Institution, Corrections Canada announced Saturday.
Bernatchez had been serving a sentence of 13 years and one month since January 2017.
The correctional facility did not immediately respond to requests for comment. No cause of death was provided in a media release.
Bernatchez was 22 when sentenced more than five years ago.
He held a correctional officer hostage for three hours at the Sept-Îles, Que., prison, threatening her with a homemade ice pick.
The officer was not physically harmed.
Bernatchez pleaded guilty to the 14 counts related to the incident.
He was charged with pointing a firearm, disguise with intent, robbery, uttering threats to cause death, riot, hostage taking, assault causing bodily harm and prison breach with violence.
Other charges were possession of a Schedule II substance, breaking and entering, having a prohibited weapon in vehicle, the discharge of restricted and prohibited weapon with intent, intimidation of a justice system participant, failure to comply with probation rules, mischief in relation to other property and conspire to commit indictable offence.
Fourth death of inmate in province
This is the fourth death of an inmate in New Brunswick in the last few months.
Two recent deaths were from the Madawaska Regional Correctional Center, including 24-year-old Jarrett Lorne Lunn and 40-year-old Wesley Robert Geneau.
Each was found unresponsive in his cell.
Skyler Sappier, 28, a member of the Neqotkuk First Nation, formerly known as Tobique First Nation, was serving a sentence at the Saint John Regional Correctional Center when he died in hospital on Jan. 31.
Coroner inquests have been ordered for all three deaths.