The 25-year-old ABC councillor replaces outgoing veteran MLA Sydney Anderson, who last week announced that he was not standing for re-election.
Mr Buckley will run alongside Carla Lockhart as the DUP look to hold their two seats in what is sure to be a hotly-contested constituency.
In a statement, Mr Buckley, who was first elected as a councillor after topping the poll in Portadown in May 2014, paid tribute to Mr Anderson.
“Firstly I would like to take this opportunity to thank outgoing MLA Sydney Anderson for the excellent representation and service he has provided to the people of Upper Bann for over six and a half years in the Assembly,” he said. “Sydney always saw it as an immense honour and privilege to be able to represent his local community and provided a great example to follow through his work ethic and commitment. I wish Sydney well for the future and will always be thankful for the support and encouragement he has provided to me during my political career to date.”
Mr Buckley said he had been left “humbled” by the party’s decision to select him for the election.
“Since I first entered frontline politics as a councillor I have always prided myself as a grassroots worker and have always sought to be a strong advocate and voice for the local area,” he added.
“I will be asking for the support of the people of Upper Bann in the weeks ahead and I am humbly requesting that they put their trust in me so that I can continue to provide them with the first class representation they deserve. Tough political times lie ahead, but if the electorate put their trust in me I will give my all to being their voice. I can assure the electorate that if they provide me with the opportunity to serve Upper Bann at Stormont I will not let them down.”
Doug Beattie and Jo-Anne Dobson are running again for the Ulster Unionists while John O’Dowd and Nuala Toman are running for Sinn Fein. Dolores Kelly is trying to win back her former seat for the SDLP.