Jonathan Harmsworth, 4th Viscount Rothermere

Jonathan Harold Esmond Vere Harmsworth, 4th Viscount Rothermere (born 3 December 1967) is a British viscount and inheritor of a newspaper and media empire founded by his great-grandfather Harold Sidney Harmsworth. He is chairman of DMG Media, formerly Associated Newspapers, a media conglomerate which includes the Daily Mail.

Rothermere was educated at Gordonstoun School and Duke University.

Harmsworth held various positions in Associated Newspapers and was managing director of the Evening Standard, when the sudden death of his father in 1998 resulted in his becoming the controlling shareholder and chairman of Associated and of its parent Daily Mail and General Trust just before his 31st birthday. One change he has instituted since becoming chairman is requiring directors to retire at age 75.

In 2013, Private Eye reported that Viscount Rothermere falsely claims non-dom status, in order to avoid paying tax on his stately home, Ferne House. This move saves him several millions of pounds in tax annually.

He was a supporter of the former Conservative Party leader David Cameron.

He ranked fourth in the Publishing, Advertising, and PR section of the Sunday Times Rich List 2013 with an estimated wealth of £720 million. In April 2015, the Sunday Times estimated his net worth at £1 billion He has non-domicile tax status and owns his media businesses through a complex structure of offshore holdings and trusts.

The BBC's Newsnight programme at the end of January 2017 reported that former prime minister David Cameron had approached Lord Rothermere to sack Eurosceptic Paul Dacre, the editor of the Daily Mail in the run up to the 2016 EU membership referendum. A representative of Lord Rothermere refused to confirm or deny the story, although a spokesman for Cameron confirmed that had tried to persuade both Dacre and Rothermere over the vote. Rothermere's representative told the media: "Over the years, Lord Rothermere has been leant on by more than one prime minister to remove Associated Newspapers’ editors but, as he told Lord Justice Leveson on oath, he does not interfere with the editorial policies of his papers".

Rothermere married Claudia Caroline Clemence, daughter of Terence J. Clemence, on 15 July 1993. They have five children:

• The Honourable Vere Richard Jonathan Harold Harmsworth (b. 1994)
• The Honourable Eleanor Patricia Margaret Harmsworth (b. 1996)
• The Honourable Theodora Mairi Ferne Harmsworth (b. 2001)
• The Honourable Iris Geraldine Lilian Harmsworth (b. 2004)
• The Honourable Alfred Northcliffe St. John Harmsworth (b. 2010)

In 2002, The Guardian reported that Rothermere had fathered another son from a relationship prior to his marriage. Testimony from the Leveson Inquiry seems to confirm this.