A family statement said his relatives were “devastated beyond words” at the loss of “the glue that bound us together”.
Labour leader Jeremy Corbyn said the death was “terrible and deeply shocking news”.
Mr Sargeant, who is understood to have taken his own life, was a “much loved husband, father and friend”, a statement released by the family said.
The statement said: “Carl was a much loved husband, father and friend. He wasn’t simply a part of our family. He was the glue that bound us together. He was the heart of our family. We loved him so very much.
“He was the most kind and caring husband, father, son and friend.
“We are devastated beyond words, and we know our grief will be shared by all those who knew and loved him.
“We are in shock and grief. We ask that our privacy is respected at this time.”
A spokeswoman for North Wales Police said: “We are investigating an incident at an address in Connah’s Quay.
“There are no further details available at present. We will provide an update in due course.”
Alyn and Deeside AM Mr Sargeant was suspended from party membership and “removed” from his cabinet role in Cardiff Bay on November 3.
He said he was told about the existence of the allegations against him by First Minister Carwyn Jones but had not been given details about the claims.
Mr Sargeant described the allegations about his personal conduct “shocking and distressing” and he had hoped for an urgent investigation to give him the chance to clear his name.
Deputy Labour leader Tom Watson said: “I campaigned with Carl for many years.
“He was a powerful voice for working people and Wales.
“He put community at the heart of his politics and was respected by his constituents for it.
“My love and prayers are with Carl’s family today.
“This is a tragedy beyond words.”
Mr Jones said: “Carl was a friend as well as a colleague and I am shocked and deeply saddened by his death.
“He made a big contribution to Welsh public life and fought tirelessly for those he represented both as a minister and as a local assembly member.
“He will be a great loss both to our party and to the Senedd.
“My heartfelt sympathies are with his family at this difficult time.”
On Monday, Mr Jones said he was forced to take action after becoming aware of “certain incidents” with women allegedly involving Mr Sargeant.
He told ITV News: “My office spoke to the women involved, as a result of those discussions I felt there was no choice other than to refer the matter to my own party for further investigation.”