The 69-year-old has become a Yorkshire institution after fronting the corporation's Look North programme for most of the last 38 years.
For the last seven, he has shared the screen with Amy Garcia, who will now continue to front the show on her own following Gration's last show next Wednesday (October 21) - the day before his 70th birthday.
The Bradford-born news veteran told The Yorkshire Post: "It’s been quite a traumatic day you could say... I’m incredibly sad, I’ve been very emotional about it.
"It’s been a very difficult time to be honest, when you have done what I’ve done for so long - to suddenly realise that you are going to wake up in the morning and not be going to work".
The announcement follows on from BBC cutbacks, announced in July, that will see Look North reduced to a single presenter and fewer hosts on local radio stations.
Mr Gration, 69, said: "Obviously the BBC needs to make significant savings - that clearly played a part but this seems to be the right time to do it as well and have a little bit of time to do different things."
Harry joined the BBC in 1978 and has presented Look North since 1982.
He said: "For the past four decades, it's been a privilege to meet the people of the county I love.
"Make no mistake, these good folk are the heartbeat of the programme.
"I've worked with the best of the best and leave Look North in the good hands of Amy and the team, although I don't know how (BBC weatherman) Paul Hudson is going to cope without me checking his forecasts.
"I'm looking forward to some new broadcasting adventures and some special time with my family and a certain one-year-old."
He added: "I've interviewed every prime minister since Margaret Thatcher, covered every major Look North story even at the expense of my holidays, and I wouldn't have changed a thing.
"I've always lived the story. Horrendous events such as the devastating news of Jo Cox's death, the disastrous floods of recent times, the Bradford Riots, Hillsborough, have always affected me. They were always an assault on my county.
"Stand-out moments include raising over £800,000 on a tandem, pushing a sofa and being tied to Paul (Paul Hudson, the weather presenter): three challenges my body will never forget."
The Director of BBC England, Helen Thomas, said Harry was a “broadcasting legend”, adding: "He is a true professional, a Yorkshire treasure and it has been a privilege to work alongside him.
"To call Harry a broadcasting legend would be an understatement.
"Over the past 40 years he has been a constant and reassuring presence on our screens, and it is testament to his skill that he has been as much at home interviewing the people of Yorkshire as he has prime ministers and royalty.
"Despite his extraordinary tenure, Harry never lost his passion for news, particularly regional news, and that shined through every evening."
Bradford-born Gration joined the BBC in 1978 after working as a history teacher, and joined Look North in 1982, although he left for a spell working on BBC South Today in the 1990s.
He covered nine Olympic Games for the BBC and won two Royal Television Society (RTS) awards for his sports documentaries: White Rose In Africa in 1992 and Dickie Bird: A Rare Species in 1997.
And he won the RTS Best Presenter award twice.
Reflecting on his announcement, Harry said it was a "retirement of sorts," as he hopes to continue with some of his own media related projects in the future.
“I don’t think retirement is the right way of looking at it, it might mean just a realignment of the kind of things I’m going to do.
"I still plan to do a little bit of work - a lot depends on what comes up as well because I want to do things that I want to do rather than do things just for the sake of it".
He added: "The odd column here or there would be lovely... as it is at the moment I am just taking it all in."
Harry said he had concerns for the future of broadcasting and maintaining "standards" amid both national and regional cutbacks in the industry.
He said: "Anybody involved in broadcasting at the moment would be concerned about the number of people who are losing their jobs all over the place, of course I'm very concerned about that.
"The one thing we want to try and do is to make sure once this is all over - that the standards are maintained. I'm pretty confident that will be the case for Look North, that once Covid goes, and it will go sometime in the future - we will be able to look forward to a more normal Look North and a normal programme again.
"But at the moment, my colleagues are working through extreme challenges, just as they are at The Yorkshire Post and similair organisations to make sure that the programme and the paper goes out. And for that I've got wonderful respect for everybody."
Yorkshire-born Harry began filing match reports for the BBC while working as a history teacher in the mid ‘70s. He joined BBC Radio Leeds as Sports Editor in 1978, before going on to commentate on the Olympics and Paralympics and present ionic shows such as Grandstand, Sportsnight and even Match of the Day.
He said: "One of the things I’ve loved more than anything is to get to really understand and appreciate what the Yorkshire sense of humour is, and the Yorkshire character and that is something which will live with me for ever really and the kindness of people. And the bluntness of people at the same time".
Many will remember Harry fondly for his inspiring charity work, which saw him undertake several exhausting challenges for BBC Children in Need and BBC Sport Relief, raising hundreds of thousands of pounds for good causes and cheered on in person by thousands of viewers. These included pushing a sofa around Yorkshire and walking 120 miles with one leg strapped to weather presenter Paul Hudson.
Amy Garcia said: "It has been an absolute honour to share the red sofa with Harry for the past seven years: a Yorkshire legend, a mentor and a dear friend.
"Look North is a family and Harry has been at the heart of it for so long. He will be missed by the whole team and our loyal viewers."
Harry added: "Thank you to my audience for being so loyal, they've been with me through the good times and the bad times, when I was poorly and they have been fantastic and they've been fantastic - I've never forgotten that.
"As for legacy... I just hope the people who continue to work for Look North will have a passion for this county the way I have. I love this place, I love it with a passion, I don't like knocking it in any shape or form.
"I like to look at the good things. And I hope again, when Covid is all over we can back to celebrating what Yorkshire is all about - which is being the best county and the best place to live in the world."
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