Bailey announced in May that she would step down from the publisher of the Daily Mirror tabloid after shareholders took issue with her large pay package at a time of falling profits and sales.
Since the announcement the group has fired the long-serving editors of its daily and Sunday tabloids and moved to a seven-day publishing model to improve efficiency.
Trinity Mirror said finance director Vijay Vaghela would work with the newly appointed chairman David Grigson to run the group until a new chief executive is found.
“Despite the deep economic downturn, the actions she has taken with her team have ensured the company has consistently delivered robust profits,” Grigson said. “We wish her well for the future.”