The highly regarded Johnson is understood to have handed in his resignation on Friday. He is mulling over several offers of employment.
He had been promoted from the post of commercial director to head the accommodation services division, which has been seen as a weak link in the group. A warning issued in January that profit would be £12m below expectations drew attention to several contracts in the accommodation division.
Johnson is, however, to be replaced by a big hitter. Former Skanska boss Robert Wallace will replace Johnson on 1 July. Johnson will stay with Jarvis through the summer to manage the handover.
Wallace was deputy chief executive of Skanska UK from 1998 to 2003. Before that he spent 13 years in Hong Kong as finance director of Gammon, Skanska's South-east Asian joint venture.
Robert Wallace’s background in finance and large-scale projects makes him ideal for the task ahead
Kevin Hyde, Jarvis chief executive
One former colleague described Wallace as an accountant rather than a building man, but added that this might be beneficial to Jarvis, given its problems.
Kevin Hyde, Jarvis' chief executive, said: "Robert Wallace's knowledge of the construction sector, both in the UK and abroad, together with his background in finance and the general management of large-scale complex projects, make him ideal for the task ahead."
In a further boost to the company, it was confirmed that Steven Norris would become chairman on a permanent basis. Norris took over from Paris Moayedi last year, but his political activities prevented him from committing himself to the role.
Norris had said that he would stand down if he won the London mayoral election last week, in which he stood as the Conservative candidate. He lost to the incumbent Ken Livingstone, who was standing for Labour.