John Mooney starred in the victory, which was the third time in a row the team had lifted the trophy.
Mooney took 10 wickets in all during the two-day match to help Ireland to the historic win.
Afghanistan needed a massive 347 runs to take the win following an impressive second innings display from the men in green on Thursday.
The Afghans took 136 for five overnight into the final day on Friday, however, strong batting from Rahmat Shah and Mohammad Nabi gave a glimmer of hope to the team.
However, a change of ball proved all the difference and Max Sorensen got Nabi leg before wicket for 49, after 174 balls.
After that, victory was all but assured with John Mooney taking the last four wickets.
In a touching gesture skipper William Porterfield allowed Trent Johnston to collect the trophy after he was left sidelined for the match through injury.
The victory brought a fitting end to Johnston's illustrious career in green which has seen him collect four winners' medals in the competition.