The 23-year-old hooker finally made his Ireland debut against Fiji on November 21, after previously being an unused replacement on three separate occasions in 2009.
And the former Munster No2, who moved to Connacht for first-team rugby due to the presence of Jerry Flannery at Thomond Park, admits the call to represent his country came as a surprise despite it being everything he's ever worked for.
"Making the 22 for the Australia match was a huge shock on one hand but at the same time it offered a sense of self-fulfilment," Cronin told the Irish Times.
"It's a reward for hard work. I know I am fortunate because not everyone gets that opportunity."
Having sat on the bench behind Rory Best in the summer games against Canada and the USA, Cronin was again simply a squad player in that drawn game against the Wallabies in the first of three November internationals.
Cronin played his part in the lead up to the Croke Park encounter but he wasn't required on the field as Ireland failed to win for the only time in the calendar year.
But despite not taking part in any of the action, Cronin admits that being in the matchday squad for his first international on home soil was a memorable occasion.
"I wasn't too nervous in the run-up to the game but as the day approached I started to feel the nerves," added Cronin.
"I was able to enjoy the anthems at Croke Park and pick out my family in the crowd. I knew they were proud and that they would be enjoying the day almost as much as I was.
"Obviously you're desperate to get on the pitch but, as in the two matches during the summer, the call didn't come."
That call did eventually arrive a week later when Cronin came off the bench to face Fiji at the RDS.
Declan Kidney's men ran out comfortable 41-6 winners and Cronin made a positive impact when his time to shine finally came around, even if he had begun to wonder whether he would always remain unused and uncapped.
"I was too excited to be nervous when I got the call. The only thing you focus on initially is getting your hands on the ball, doing something positive for the team.
"I was fortunate that I got to carry ball a few times and that definitely helps you to settle.
"It was a great venue for that match because it guaranteed a brilliant atmosphere that would have been lost with the same crowd in a bigger stadium.
"I suppose by that stage I thought I might never get a chance."
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