Patrick Desautels issued a brief press statement late Monday, 24 hours after authorities were called to a home on Turcotte Street in Drummondville, about 90 kilometres northeast of Montreal.
Police responding to a 911 call discovered the bodies of four-year-old Loïc and his sisters, Laurélie, five, and Anaïs, two.
"We are gathered as a family right now, and this drama has left us without words," Desautels said in the written statement. "The police investigation will tell us more about the circumstances. What happened defies explanation."
He added that he loved his three children deeply and will miss them for the rest of his life.
Desautels has agreed to meet reporters on Tuesday. He asks that family members then be allowed to grieve their loss in private.
Police wait to talk to mother
Quebec coroner's office said Monday it was to perform autopsies on the bodies of the children.
Their 33-year-old mother, Sonia Blanchette, remains in hospital with undisclosed wounds.
"Once her health improves enough for us to meet her, we will do so as soon as possible," said Sûreté du Québec spokesman Sgt. Daniel Thibeaudeau.
CBC's French service, Radio-Canada, reports that authorities do not believe her injuries to be life-threatening.
"We're still piecing together exactly what happened," Thibeaudeau said, adding that several witnesses have been interviewed, including the grandmother of the children.
Neighbours who spoke to CBC News on Sunday said the mother had lived alone with the three children in the second floor of a duplex for about two years.
CBC News has learned Blanchette lost custody of the children early in 2012 and had been awarded visiting rights once every two weeks, to be supervised by the children's maternal grandmother.Suggest a correction