Elliott joined the company in November 2012 from horse racing and hotel specialist Arena Leisure.
During the last year he oversaw McCarthy & Stone’s successful £527m refinancing and the company latest results for the year ending 31 August show a 21% rise in revenue to £310.8m and a 15% increase in EBITDA to £46m.
Chairman, John White, said: “Mark will be leaving the business well-financed and in a strong position to take advantage of a significant market opportunity in the retirement housing sector.
“The shareholders and directors thank him for all of his efforts and acknowledge his role in moving the business forward.”