L/Cpl Kyle Cleet Marshall, of the 2nd Battalion The Parachute Regiment, died after being caught in a roadside bomb blast in the Nahr-e Saraj district of Helmand province.
The 23-year-old, from Newcastle upon Tyne, had been due to marry his fiancee, Hayley, in July.
The UK death toll since operations began in Afghanistan in 2001 is 357.
Lt Col Andrew Harrison, commanding officer of the 2nd Battalion The Parachute Regiment, said: "He died as he lived, at the front, guiding his men, surrounded by friends and at the very tip of the battalion spear."
He said that, shortly before his death, L/Cpl Marshall had led his team in the discovery of a huge bomb-making factory, where 35 devices were found.
"This discovery will undoubtedly save numerous colleagues and locals falling prey to the most insidious of insurgent threats.
"His friends have lost the closest of mates and the most able of colleagues. The battalion has lost a stunning young leader and a bright hope for the future," he said.
Describing him as a "charismatic, upbeat Geordie," his commander said he was "ice-cool under fire and a natural leader always".
Lt Col Harrison added: "He mentored, coaxed and taught his soldiers with consummate passion and consistent diligence. He was ever-optimistic, even in the bleakest of circumstances, and could charm all he met. He is irreplaceable."
L/Cpl leaves his father, Garry, mother, Olywn, and fiancee, Hayley, whom he was due to marry after the tour.
His family said in a statement: "Kyle was a very lively, outgoing, loving and much-loved son."
The MoD said L/Cpl Marshall was a keen footballer, a passionate Newcastle United supporter, and had played to county level in his youth.
A soldier killed in a blast in southern Afghanistan on Monday has been named by the Ministry of Defence.