Martin Clarke relaunched the website in 2008.
MailOnline editor-in-chief and chief executive Martin Clarke has announced he is stepping down.
His departure is the latest in a series of changes among senior staff at the Daily Mail’s parent company, the Daily Mail and General Trust (DMGT).
Mr Clarke, who relaunched MailOnline in 2008 and helped grow it into a major news title, will also step down as publisher of the trust’s media arm, DMG Media, at the end of February.
Rich Caccappolo will take over his responsibilities for “digital revenues, platform and product” as the new chief executive of DMG Media.
Mr Clarke said in a statement: “Earlier this year I indicated to Lord Rothermere that, after 12 incredible years building MailOnline into one of the world’s biggest news websites and having established it as a substantially profitable business in its own right, I wanted to pursue new challenges.
“I will therefore be stepping down at the end of February, although I will remain available to the company until the end of 2022 and will, of course, do everything I can to assist in finding a new editor for MailOnline which must count as one of the most exciting and rewarding news jobs in the business.”
Mr Clarke joined the Daily Mail in 1987 and was made editor of the newly launched Scottish Daily Mail in 1995.
He re-joined DMGT in 2001.
Lord Rothermere, chairman of DMGT, said: “I have had to reluctantly accept Martin’s resignation as he is without doubt one of the greatest editors of his generation; and, I am eternally grateful to him for all his immense hard work and genius over the years.
“The Daily Mail is great because of the hard work of many not just the few.
“Martin leaves behind him a legacy of an impressive number of highly talented and committed people across the company who will continue to build upon what he has created and keep the Daily Mail a huge success across the globe.
“I wish him the best of luck with his future endeavours and very much hope that we continue to be in partnership on future projects.”
Last month it was announced that former Daily Mail editor Paul Dacre is to return to DMG Media as editor-in-chief.
The news came shortly after he withdrew from the race to become the next chairman of media watchdog Ofcom, claiming the civil service had influenced the selection process because of his right-of-centre “convictions”.
Recent months have also seen Mail On Sunday editor Ted Verity replace Geordie Greig at the helm of the Daily Mail.
Mr Verity was made editor of Mail Newspapers, which includes overall responsibility of the Daily Mail and The Mail On Sunday.