The appointment of Wallace has resulted in the departure of Des Kelly, acting editor of the Daily Mirror, who took over from Morgan after he was sacked over the publication of fake Iraqi prisoner abuse photos.
Kelly had also gone for the Daily Mirror editorship, but he was never strongly tipped to win the role following Morgan's dramatic departure when the Iraq photos were proved fake and the paper had to make a front-page public apology.
Wallace faces a tough job to restore the Daily Mirror's sliding fortunes. In the most recent newspapers ABCs, published last week, the Daily Mirror lost more than 41,000 sales since the publication of the fake pictures that purported to show British soldiers torturing Iraqi prisoners with sales down to 1,846,734, a drop of 2.19% on April.
Most recently, Wallace has been standing in as acting editor of the Sunday Mirror for its editor Tina Weaver, who has been on maternity leave and was also strongly tipped for the job editing the daily.
Weaver was seen as the leading contender for the post, which would have seen a woman edit the Daily Mirror for the first time, after News of the World editor Andy Coulson turned the job down last week.
Wallace, 43, was previously the Daily Mirror's US editor based in New York, and has also held the positions of showbusiness editor and head of news. As well as roles at Mirror titles, he has also worked at the Daily Mail and The Sun.
"I'm going to be working with the most talented team in Fleet Street. The greatest challenge for national newspapers is circulation. I'm confident that we have the team, the talent and the will to tackle this challenge and I look forward to even greater success for the Daily Mirror," Wallace said.
At the same time, Trinity Mirror has announced that Ellis Watson, general manager of national newspapers and former Sun marketing director, has been promoted to managing director of national newspapers with immediate effect.
Watson will, in his new role, have the editors of the UK national titles, the Daily Mirror, Sunday Mirror and The People, reporting to him. Previously, the editors had reported to chief executive Sly Bailey.
In addition, Watson will continue to have full responsibility for the Scottish national titles, the Daily Record and Sunday Mail.
According to Watson: "Richard has bags of ability and huge experience in tabloid newspapers. The Daily Mirror has a fabulous heritage and Richard's job will be to build on that as we go forward.
"With his talents, and those of the fantastic Mirror team, we have a very bright future ahead of us."
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