The 36-year-old actor, a real-life East end boy, has been cast as Mick Carter, brother to Shirley Carter (Linda Henry). He will be joined behind the bar by his wife Linda, played by actress Kellie Bright.
"I'm so excited about starting a new chapter in my career," said Danny, who previously appeared as a football hooligan in Football Factory. "I cannot wait to become part of the East End family."
Patriotic family man Mick is described as a "bloke's bloke" who is also a big softie. He and Linda were childhood sweethearts.
"He thinks nothing of throwing on Linda's pink dressing on and cooking breakfast for the family in the morning before getting the beer barrels ready downstairs," the BBC said.
Executive producer of the show Dominic Treadwell-Collins has been behind an overhaul of the cast, recruiting new faces and dropping other characters.
He said: "I'm so excited to have actors of Danny and Kellie's calibre joining what is an already strong and talented company of actors.
"Having been together over 20 years, Mick and Linda have a good marriage and an easy shorthand with each other - but can also still fight like teenagers. They will laugh, cry, argue and make-up … much to the embarrassment of their children and the delight of Albert Square's residents.
"Mick and Linda still love each other, no matter what life throws at them. And moving from Watford to Walford, life's about to throw them a few curve balls."
Danny had previously discussed a role on Albert Square in 2009, but decided against it.
"I quite liked the idea," he said at the time, "but actually, in reality, I just got cold feet.
"Just from having a meeting, it's all over the newspapers and it gave me the horrors. Imagine if I went in it?"
It has already been revealed that former Holby City star Luisa Bradshaw-White is to join the EastEnders cast as Tina Carter, another of Shirley's siblings.