Stuart Murray, from Ballykelly, Co Londonderry, died on Saturday when his vehicle was ambushed in Herat while he was on his way to the airport in Kabul.
The father of two, who had just turned 40, had been working for a private security firm in the war-torn country, having left the regular British Army two years ago after a distinguished 21- year career.
At the time of his death he was on leave of absence from the Territorial Army in which he served as a staff sergeant.
'Loss'
Heartbroken Sheena Murray said she and the couple's two children, Georgina and Joshua, were devastated by his death.
"Words cannot begin to describe the loss that we as a family are feeling," she said.
"Stuart was a warm, caring family man who lived for his children - he meant the world to us."
Colleagues of Mr Murray are due to escort his body home in the coming days.
A former platoon sergeant with the Royal Irish Regiment, he was involved in the NATO-led operations in the former Yugoslavia in 1991 and served in the Falkland Islands and Germany.
When the regiment was disbanded in 2007, he joined the TA in Northern Ireland with 40 (Ulster) Signals Regiment.
In January of this year he requested a leave of absence to go to work as a security guard in Afghanistan.
In a statement released by the Ministry of Defence, his widow Sheena thanked all those who passed on their sympathies and asked for privacy to mourn her loss.
"We are deeply grateful and sincerely moved by the expressions of sympathy and support that we have received but we would now ask that we be allowed time, space and privacy to grieve," she said.
'Great soldier'
Mr Murray's commanding officer in the TA, Lieutenant Colonel Stewart McConnell, described him as a great soldier with an infectious zest for life.
"Staff Sergeant Murray embodied all that was great about a Territorial Army soldier," he said.
"From his arrival in the regiment in 2007, his impact was immediate and his attitude and professionalism had a hugely positive influence upon all around him."
"Fit, enthusiastic and diligent, he could be the found at the centre of every activity, from military or physical training to supporting the Sergeants' Mess."
"My memory of him will be of a soldier with a great sense of humour and a zest for life that was infectious."
"As well as being a professional soldier in every sense of the word Staff Sergeant Murray was a family man at heart and enjoyed nothing more than spending time with his wife Sheena, daughter Georgina and son Joshua.
"He will be sorely missed by every member of my regiment and our thoughts and prayers at this terrible time go out to his family whom he loved so dearly."
'Tragedy'
His employer Compass Security said he was "held in very high regard by his team and by all those who knew and worked with him."
In a statement they said: "He will be greatly missed".
"This is a tragedy for Stuart's family and we extend them our deepest sympathies. "
"Stuart was repatriated to Kabul with the assistance of the international military force in Afghanistan and he will be escorted home to Northern Ireland by a senior Compass manager and several of his closest work colleagues."
"The Compass team is a tight-knit family of highly-trained professionals like Stuart Murray."
"Our teams work in difficult circumstances doing vital work on behalf of the international community and we are extremely proud of their contribution to nation building in Afghanistan."
"The thoughts of all at Compass are with Stuart's family and we will do everything we can to support them through this difficult time."