The 23-year-old took a further step towards doing that on Wednesday evening when he produced a thrilling cameo as a second-half substitute on his Republic of Ireland debut against Latvia.
Johnston is currently playing his football in Portugal on loan at Vitoria Guimaraes in an effort to regain his best form after a serious knee injury cost him almost a year of his fledgling career and left him struggling to force his way into Bhoys manager Ange Postecoglou’s plans.
Asked if he sees himself back at Celtic in the longer term, he said: “We will see. I want to enjoy football and I want to play, I don’t want to sit on the bench and not get games. I just want to feel important.
“Last year I did still play 20 games for Celtic, so it’s not like I was pushed out the door. I played in a cup final for him [Postecoglou], he gave me an extra year when I left the club, so that gave me the faith to say he wants me to come back to the club and produce.
“There’s a lot of players in that position, maybe six or seven wingers including myself. I needed consistency, needed more minutes. We had an honest conversation and he said it was best I went elsewhere to get them minutes and I was fine with that.
“I needed a bit of a freshen-up. Opinions on me weren’t accurate and I wanted to change that. I had to get away from the UK, to be honest.”
Glasgow-born Johnston, who represented Scotland at Under-15s, Under-19s and Under-21s levels, qualifies for Ireland through his Derry-born grandfather and his switch of allegiance was approved by FIFA earlier this month.
Aiden McGeady made a similar decision as a teenager and faced stern criticism in Scotland as a result before going on to win 93 senior caps for Ireland, and although the latest man to declare for the Republic has also found himself in the firing line, he is comfortable with the path he has taken as he prepares for Monday night’s Euro 2024 qualifier against France.
Johnston said: “I think times have changed. I made this decision, people respect that or they don’t. I am my own man and they’ll never know the reasons why I did it.
“It’s always been talked about, it’s in my family, in my blood. My mum and dad, we had a conversation, they said, ‘Go for it if it’s what you want’.
“I have some family in Derry, some in Donegal, some in Dublin as well. I have them all over the place, but Derry is the link. I have had texts from all my aunties and stuff from all over Ireland I didn’t know I even had.”