Brian MacArthur, who has died aged 79, was a national newspaper journalist guided by a strong moral core, a respect for accuracy and an intense dislike for his trade’s darker arts. It is therefore unfortunate that his name was linked so closely to the Sunday Times’s misbegotten publication in 1983 of the Hitler Diaries, an elaborate hoax perpetrated by a German forger.

MacArthur, then the paper’s deputy editor, had relied on the diaries being authenticated by Hugh Trevor-Roper, the foremost historian of Nazi Germany and a director of Times Newspapers. After the first extract had gone to press, Trevor-Roper told the paper’s editor, Frank Giles, that he had changed his mind. MacArthur contacted the Sunday Times owner Rupert Murdoch to suggest stopping the press. Murdoch wouldn’t hear of it, arguing that the rise in circulation from publishing the diaries would outweigh any subsequent damage to the paper’s reputation.

MacArthur never shied away from his involvement in the escapade, enlivening many a dinner party with the details. Of much more significance were his editorships. He was the founding editor of Today newspaper, the first editor of the Times Higher Education Supplement, and one of the few senior executives to step away from Fleet Street for a period to edit a regional title, the Western Morning News in Plymouth.

Editors he worked under often called on him for advice, relying on his steady counsel when facing difficult decisions or calling on him to carry out delicate tasks. He also took the time to encourage and nurture young reporters and writers at the outset of their careers. Along the way, in an era when book extracts were regarded as major sales-winners, he was the canniest negotiator of serial rights, greatly helped by having built up an unrivalled network of publishing contacts. A prolific reader, he later turned to writing and became an author.

He was born in Chelmsford, Essex, the only child of Sylvestor, an education officer, and his wife, Marjorie (nee Wybrow). From the age of seven he boarded at Brentwood school, where he enjoyed its sporting opportunities.

At 13, after his family had moved to Ellesmere Port in Cheshire, he attended Helsby grammar school and began to broadcast about cricket and football on hospital radio. At Leeds University he was news editor of the student newspaper, and on leaving in 1962 he spent a couple of years on the Yorkshire Post, followed by reporting stints on the Daily Mail (1964-66), the Guardian (1966-67) and the Times (1967-71), where he became education correspondent.

He was tasked by the Times’s editor-in-chief, Denis Hamilton, with creating the Times Higher Education Supplement, which he edited for five years with considerable sales success.

In 1976 he returned to the Times as home news editor, staying for two years before accepting an offer to be deputy editor of the London Evening Standard. It did not suit him and he returned to the Times, eventually becoming joint deputy both of that paper and of the Sunday Times.

Disappointed at not being chosen to take the helm at the Sunday Times, he gamely helped Andrew Neil settle in as editor until making an unusual move in 1984 by going to Devon to edit the Western Morning News. He might well have stayed there longer, but had served barely 18 months before a new press entrepreneur, Eddy Shah, came calling.

Shah asked MacArthur to launch a new national title, Today, which would be produced without trade unions, with computer technology and with colour pictures (other nationals were still monochrome at the time). It proved to be a tough assignment because Shah expected him to go to press without the usual opportunity to produce dummy editions. MacArthur also found it difficult to explain how his so-called “quali-pop” editorial agenda could attract an audience large enough to satisfy advertisers.

The result, as he was to admit in a candid book about Today, was a disastrous launch followed by internal rows, a lack of readers and the loss of millions of pounds. Shah was soon forced to sell the paper to Tiny Rowland’s Lonrho group, and MacArthur walked out after only a year in charge.

He was rescued by Neil, who took him back to the Sunday Times in 1987 as executive editor. One of MacArthur’s first acts was to offer help to me, a newcomer to the paper and an object of suspicion by staff due to my arrival from the Sun. He proved to be, just as he was to so many journalists down the years, a loyal and steadfast friend.

Unfailingly courteous and known for his cheery outbursts of laughter, he was one of the trade’s greatest enthusiasts and one of its fairest critics. From 1987 he began to write a column about the press for the Sunday Times, notable for its balance, that ran for 18 years.

In 1991 MacArthur moved back yet again to the Times, until, in 2006, he took up the post of assistant editor of the Daily Telegraph, which he left in 2010. By that time he was immersed in researching and writing books. The two that gave him most pleasure were Surviving the Sword (2005), memories of prisoners held by the Japanese during the second world war, and For King and Country (2008), an anthology of voices from the first world war.

MacArthur is survived by his third wife, Maureen Waller, the author and historian, whom he married in 2000; and by two daughters, Georgie and Tessa, from his second marriage, to Bridget Trahair, which ended in divorce.

• Brian Roger MacArthur, journalist, born 5 February 1940; died 24 March 2019