In a keynote address on Christian citizenship at Belfast City Hall this week, Dr John Sentamu said it was a "distressing and evil" aspect of modern society that "so many people feel excluded".
"We need to understand the reasons for this sense of exclusion, otherwise we cannot hope, as Christian citizens, to build societies that are safe, generous and magnanimous," he said.
"The implications of exclusion, whether it is actual or perceived, can have terrible consequences."
The Archbishop was speaking at the Presbyterian Church's Citizenship, Covenant and Christ Conference to mark the centenary of the Ulster Covenant against the establishment of a home rule parliament in Dublin.
He told Christians to remember the transforming love of Christ so that "we too may change and be agents of change in our communities".
Christian citizenship today, he said, involved being "willing to participate at every level in the societies in which we are based whilst holding fast to the values of Christ's Kingdom".
"It is integral to Christian discipleship," he said.
At a national level, Christian public engagement with politics would involve "critical solidarity".
"This means that the church stands in solidarity with those who are its elected representatives," he said.
"However, it is a critical solidarity because it is unafraid to ask difficult questions when necessary to maintain a vision of what the world could be if God's call to humanity is taken seriously."
While some churches would do this on a national level, he said it was the calling of every Christian to be an "active citizen, seeking to contribute to the building of policies and structures in which all people may flourish".
He continued: "This involves not just voting in elections, but being willing to play a direct part in helping build communities which work.
"More people volunteer their time to projects, groups and initiatives run by the church in local communities than any other single organisation in our country."