Johnston receives FIFA international clearance
Johnston, on loan at Portuguese Primeira Liga side Vitória Guimarães this season, has completed the eligibility process and is now available for selection for the Republic of Ireland ahead of the March international fixtures against Latvia and France.
Glasgow-born, Johnston qualifies for the Republic of Ireland through his grandfather who was from Derry and started the eligibility process months ago after making Ireland manager Stephen Kenny aware of his desire to play for the Republic of Ireland.
The 23-year old made his first-team debut in 2017 and has since gone on to win the Scottish Premiership three times with the Glasgow club, as well as two Scottish Cups and two Scottish League Cups.
He started in the 2019 Scottish Cup final where Celtic claimed a 2-1 victory over Hearts and also scored a decisive penalty in the 2020 Scottish Cup final where Celtic claimed a penalty shoot-out victory over the same opposition.
Johnston also has extensive European competition experience in the UEFA Champions League and Europa League, scoring against French side Rennes SC in a 3-0 win in the 2020 addition of the competition.
Currently on loan in Portugal, Johnston has enjoyed an impressive season for Vitória where he has made 20 appearances in all competitions, scoring three goals and providing three assists.
"I'm delighted to declare for the Republic of Ireland and excited for what my future holds in an Ireland shirt," said Mikey Johnston.
"Myself and my family have always been proud of our Irish roots with my grandad hailing from Derry and to potentially now play for Ireland is something that really excites me.
"It's up to me now to impress the manager and to get selected to the squad but my focus now is to break into that squad and to make an impact for the team in a big year for the team.
"I've always watched the Ireland matches and the atmosphere always looks incredible. I can't wait to play at the Aviva Stadium and hopefully create some great moments for the team."
"Mikey is an exciting player, a great individual talent and we're delighted to see him declare for the Republic of Ireland," said Ireland manager Stephen Kenny.
"I'm looking forward to seeing him play at the Aviva Stadium, dribbling in the way that he can and we look forward to helping him fulfil his potential in an Ireland shirt."