The 28-year-old admits he has had to ride a wave of emotions in recent weeks. He was plunged to the depths of despair as his Falcons side were relegated from England’s top-flight at the end of last season. But his flagging confidence levels were hauled up again by Townsend’s decision to name him in his squad for Japan ahead of try machine Huw Jones and Northampton youngster Rory Hutchinson.
Now with that show of faith, the 28-year-old is marching towards Scotland’s tournament opener with Ireland next Sunday with a strut that means business. And the Durham-born midfielder is eyeing up the Yokohama showdown as a potential springboard to the latter stages.
Harris said: “There is always a bit of worry while you wait to see if you are in the squad but once I got the call to say I was going I was absolutely delighted.
“Was it a confidence booster? Yeah, massive – absolutely. I’m feeling so positive at the moment and just want to get stuck into the World Cup now. There was a lot of competition in the centres but knowing that I’ve made it has given me a real boost.
“Starting against France in the warm-up games and scoring a try was a big moment for me, I feel like I’ve kicked on from there. I’m fully confident now.
“Going to a World Cup is definitely up there [with the best things I’ve achieved in my career]. I’ve taken things step by step – getting called up initially, then winning my first cap, then my first start.
“I was even chuffed just making it into the wider squad. So now that I’m here in Japan I don’t want to just stand still. That’s how I’ve got to where I am now, by not resting on what I’ve got.
“You have to have that ambition to better yourself. Unless you have this natural ability to be awesome all the time without putting much effort in then you have to work as hard as possible.
“Professional sport is a roller-coaster ride for most athletes with the highs and the lows you go through.
“Being relegated with Newcastle was the ultimate low. I was absolutely devastated – yet it’s the opposite feeling being named in the World Cup squad.
“But I want to go further. Personally, I want to be starting games, to be the number one. With Scotland I want to go as far as I can, to win a World Cup.
“The boys all firmly believe we can but right now we’re just stripping it back and taking it one game at time, which means all we’re focusing on is Ireland.”
Scotland will have to weather a storm both on the pitch and from the heavens next weekend.
They are forecast to take on the world’s No 1 ranked side amid a torrential thunderstorm but Harris reckons wet and wild conditions will be sweet relief after a week spent sweltering at their Nagasaki training camp.
“This place is absolutely melting but I think we’re adapting quite well,” he said. “We trained out in Portugal earlier in the summer which has helped a bit but the humidity out here is unreal.
“Once we get to Tokyo and it’s 22 degrees we’ll all be like, ‘Ah, lovely’. But it will still be tough conditions out there. It’s supposed to be raining so it will interesting.
“The game plan won’t change but the weather will dictate how much we can play. Our defence will be ready to get at them and put their skills under pressure.
“But we don’t want to over play in areas if it’s wet. We can’t mess around deep in our half but we’ve got a good enough skill set to play how we want to play.”