The 33-year-old, who is in his fourth season with Connacht, suffered two consecutive injuries last season – arm and back – that kept him from earning his first cap with Ireland despite a lengthy period training with the squad.
"When I injured my arm back in November that was very disappointing, but then to get fit and injure my back, there were definitely a few demons, " commented White at the post-match press briefing on Saturday.
"Connacht offered me a new contract though, so that really made me determined to get myself right and do right by them.
"And this opportunity came along, and that's just great.
"I don't know how many coaches would show the kind of faith that Joe has shown in me.
"He's backed me and given me a crack, and it's just fantastic to have had that chance.
"There were dark days in rehab but the carrot was always to be in the position to play in a game like this, so it's great to have done it."
While White officially became the third oldest debutant of all time in Saturday's 28-22 victory over Scotland, he admitted he "felt like a kid again" on his international bow.
"Being involved in November and in the Six Nations in the camps, that definitely helped me in terms of knowing what was expected on the field, " he said.
"I felt like a kid again myself, especially when you've got Paul O'Connell out there, a guy I've watched for a fair while.
"So I just really wanted to cherish the moment.
"If Joe's happy with what I've done on the field then hopefully I'll get the call to go back into camp on Sunday night.
"I'm just going week to week really at the moment, hopefully I can go back again.
"Marty Moore is coming back, and Michael Bent covered tighthead last week so there's plenty of options there."
The Ireland training squad will reassemble on Sunday 23rd August in advance of their next test match with Wales on Saturday 29th August at the Aviva Stadium.
Meanwhile, Pat Lam’s Connacht will travel to play Munster at Thomond Park in the third and final pre-season friendly on Friday 21st August. Kick off in Limerick is at 7:45pm. Tickets are available here.