The 20-year-old was supposed to spend 2017/18 with Newport RFC in the Premiership but instead became a Dragons regular after his professional debut in October.
After making his bow in the loss to Cardiff Blues at the Arms Park the back row forward featured in all but one fixture in all competitions.
Wainwright was named as the Dragons' newcomer of the season and an already incredible season had another magic moment when he was called up by Warren Gatland for the summer tour as an injury replacement for Josh Navidi.
He was an unused replacement against South Africa in Washington before making an impression with a cameo against Argentina in the first Test.
Wainwright, who can play across the back row, was brought on with 52 minutes gone but still racked up 13 tackles in San Juan.
That was a tally that only four players – starters Ross Moriarty, Hadleigh Parkes, James Davies and Adam Beard – eclipsed from both sides.
"I was a bit nervous sat on the bench waiting to come on but as soon as they said that I was going to go on I was really excited and tried to play as well as I could," he said.
"Nerves went out of the window and I tried to do my own jobs. I was really excited, especially because my dad was out there watching in the crowd."
Wainwright became the 1148th man to represent his country and believes mixing with other Test stars can help him avoid a testing second season as a pro in the build-up to next year's World Cup in Japan.
"Hopefully I did enough to make a good impression," said Wainwright. "I tried to play as well as I could when I went on but who knows what will happen in the next 18 months.
"It's been the longest that I have been away from home playing rugby, so that was a good experience.
"Staying with the boys all the time, getting used to a routine, preparing for the games, it's been a really good experience and hopefully I can take away the small things from the tour and take them back into my own training and routine back at home."
Wainwright will be part of a fierce battle for back row starts at Rodney Parade next season.
Head coach Bernard Jackman will also have Ross Moriarty, Ollie Griffiths, Harri Keddie, Lewis Evans, James Benjamin, Nic Cudd, James Thomas, Huw Taylor and James Sheekey as senior options along with the Under-20s trio of Taine Basham, Lennon Greggains and Ben Fry.
