The Volunteer Co-ordinator at ARC Healthy Living in Irvinestown says the games were "an emotional rollercoaster" bringing "the best out in everyone".
And now back to his day job he is determined to apply a little bit of that Paralympic spirit to his daily work ethic.
Tiernach was one of over 870 volunteers working at the Olympic Stadium each day during the Paralympics.
In previous years he was among the hundreds of thousands of spectators cheering from the stands at Athens, Barcelona and Atlanta.
But when London won the bid to host the 2012 games, the Irvinestown man knew he wanted to be more than just a spectator.
"The day London was announced as the winner, within five minutes I phoned my sister in London to say I was staying with her during the Olympics and Paralympics!" he told The Impartial Reporter, "It was a dream come true that they were coming so close to home and being involved is something I had always dreamed about."
True to form, when the opportunity arose to volunteer, he wasted no time in applying.
He says however that the role assigned to him over the course of the fortnight as games-maker was far more significant than he ever could have imagined.
"I just expected I would be doing minor jobs. But whatever I was doing, I wanted to be part of such a momentous occasion.
"We had three training days before we started -- all very intensive training, but when it came down to it, in many ways you were learning on your feet when the Paralympics actually began."
For the first eight days Tiernach's shift ran from 4.30am until 3.30pm. The final three days he worked the later shift -- 2pm until 12.30am.
"On the last night we didn't actually get finished until 2am because we were preparing for the closing ceremony. But nobody minded, we were all just glad to be doing our bit.
"The stadium was to open at 8am every morning -- our goal was to have it ready and opened before that each day. There was only one morning that it opened three minutes later!
"Each day went I back to my sister's house totally and utterly exhausted. I had blisters on my feet but I didn't care -- the whole atmosphere was just so electric that it carried you on. I was supposed to be off on the last Friday, I was so tired, but I said if they needed extra help to let me come in. It was a once in a life time opportunity and I didn't want to miss a minute of it."
Tiernach says the atmosphere throughout the Paralympics was euphoric.
"Everyone was on an adrenaline high -- it's hard to put it into words. Everyone knew that something fantastic was happening."
He says he found his spent in London inspiring.
"If you ask me I think the volunteers really made the games -- it was the best kind of example of people working together for a common goal. I will never get to be involved in anything like that again.
"The night Jason Smyth won for Ireland I was down on the track chatting to his family. And when he took out the Irish flag I was 10 feet away. I'll never get to experience something like that again."
According to Tiernach, the last night was a particularly emotional experience.
"We had been through something so amazing, and we knew we would probably never meet again.
"I got so much more out of volunteering than I ever thought I would and I suppose that's what volunteering is all about really."