The Church of England must be “more joyful and less anxious”, Stephen Cottrell, who has been named the 98th archbishop of York, the second most senior figure in the Church of England, has said.

Cottrell, 61, the bishop of Chelmsford, will replace John Sentamu, who is retiring next year. Popular within the church for his down-to-earth persona and straight-talking, Cottrell was brought up in Essex, attended a state school and studied at the Polytechnic of Central London.

He told a press conference in Church House, Westminster: “I’m a boy from a very ordinary family, from a secondary modern school in Essex, who is now called to be the archbishop of York.” There “wasn’t much church in my growing up”, he said, but watching the film Jesus of Nazareth at the age of 12 “changed my life”.

Sentamu’s retirement means the loss of the C of E’s most high-profile figure from a black or minority ethnic background. In the past, Cottrell has publicly criticised the church for its shortcomings in promoting BAME clergy into senior positions.

On Tuesday, he said: “Our record is not good, there’s no point in pretending otherwise. This is something that matters hugely to me. I hope that when I do hang up my mitre, the church will look different and more diverse.”

He said he anticipated that “one day” the church would have a female archbishop of Canterbury.

One of the powers that bishops have is the selection of people to train as priests and the appointment of clergy. “We need to use [that power] much more generously and wisely to bring more people round the table. We will be a much stronger church for having a more diverse leadership.”

Reflecting on last week’s election results, Cottrell said the UK was standing “on the edge of great change as we leave the European Union” and there were “many challenges ahead”.

He added: “Learning how to live sustainably on this earth is the greatest challenge of all … We must be one nation but also one world, one humanity.”

The scale of Conservative victory had taken the country by surprise. The church had a “particular responsibility to speak for the poorest and most marginalised. That is not always easy or comfortable,” he added. “There is a north-south divide that is shockingly real.”

Asked about the issue of same-sex relationships, which has divided the church for more than 20 years, he said there was “absolutely no place for homophobia in our church, and absolutely everyone, regardless of their sexuality, is welcome in our church”.

Among the issues on which Cottrell has spoken out is nuclear weapons. In 2016, he told a rally in London the renewal of Trident was “an affront to God”, and last year, he told the synod there were “no circumstances” in which Trident’s use could be justified given the destruction the weapons would cause.

In April, he was among 25 priests and bishops who opposed a service at Westminster Abbey marking 50 years of constant patrols by the UK’s nuclear deterrent. “It is impossible not to view this service as appearing also to celebrate the weapons themselves,” he said.

He has also called on the church to make land available for Gypsies and travelling communities who face institutional racism and ostracisation. The Christian imperative was to combat racism in all its forms, he said. “Therefore it is incumbent upon the church to take a lead on this issue, providing a voice for those who are so marginalised and discriminated against.”

Describing himself as an optimist and a “preacherman”, Cottrell said he was “humbled and excited” by his appointment.

Justin Welby, the archbishop of Canterbury, said at the press conference Cottrell was “one of the most inspiring leaders in the church. He preaches, he writes beautifully, he writes poetry, he thinks very deeply, he communicates superbly, he is not hierarchical, he’s got a huge heart that is open to the needy and poor and vulnerable. He’s a pastor.”

Sentamu said Cottrell had “the gospel in his belly and a tiger in the tank. His nomination as my successor has gladdened my heart and he can rely on my prayers.”