He was previously director of the construction division at Speller Metcalfe.
He succeeds Tony Shaw, who partially retired last year, stepping sideways from the managing director position to become pre-construction director.
Des O’Neill takes charge of the contractor’s Malvern and Wolverhampton operations, which both fall under the company’s Malvern Limited branch.
Speller Metcalfe also has offices in Gloucester and London.
Joint group managing director Steve Speller said: “Over the last 18 months the directors have been working together to enable a more efficient crossover of resources between our regional teams. This strategy has driven benefits both in terms of efficiency, but has also provided opportunities for staff development.
“Following continued growth and success of our Wolverhampton base, Des has become increasingly engaged in the management decision process at Malvern, gradually taking ownership of broader responsibilities. We are therefore delighted to recognise and formalise his contribution as the new managing director.”