Johnson's surprise appointment this week comes after the sudden departure of Dennis Brant, 50, a lifelong Wimpey man who had been in the chief executive's seat since February 1999.
Wimpey said in a statement that Brant had resigned for personal reasons. A spokeswoman explained that he wanted to spend more time playing golf and sailing.
Johnson restructured Rugby from a multi-product materials conglomerate to a cement-and-lime group, then steered it towards acquisition by RMC at the end of 1999. Wimpey chairman John Robinson appointed Johnson after briefing head-hunters.
Analysts have welcomed the appointment, saying Johnson has a reputation for making the kind of radical structural and strategic changes that Wimpey needs.
They believe that Brant started to deliver on his five-year improvement programme, but insist that his goals were not ambitious enough in a buoyant market.
One analyst said: "Johnson's brief should be to make assets perform, or sell them.
"That exercise hasn't been done rigorously enough in the past." He pointed to the example of Crest Nicholson, which has sold its Northern housebuilding operations to release money for the more profitable South.
A second analyst commented: "People rate Peter Johnson. He secured a nice price for Rugby shareholders, so this might start tongues wagging about for-sale signs." There has also been speculation that Johnson may have been appointed to set in motion some sort of corporate action, possibly a management buyout, given Wimpey's low share rating.
Wimpey's interim results for the six months to 30 June show turnover of £694.1m and pre-tax profit of £48m.