The Blues midfielder made his debut coming off the bench 77 minutes into Ireland's 2-1 win in Dublin.
Both of the Irish goals, scored by Kevin Doyle and Liam Lawrence, came in the first half of the match at the RDS Arena with the visitors pulling one goal back through Luca Barrios 14 minutes into the second period.
I'm really happy to pull on the green jersey for a full international -- it was a good feeling," Fahey told the Irish Independent.
"It was just great to get on. I felt brilliant, there were no nerves. It's been a long time coming. I didn't get a touch for about 10 minutes after I came on but it was great to get my first touch and get on the ball a bit.
I got a decent reception. I was really happy with it. It was a proud moment for me.
"I'd friends and family here as well -- a few of my cousins, a couple of uncles, my brother and some close friends were here. It's great that they were here for my debut."
The Republic next entertain Algeria at the same venue in another international friendly on Friday, 28th May.