The company chief digital officer, Ulrik Begntsson, will succeed Bowcock, who will resign as chief executive on September 30 but stay on as an employee until the end of the year to ensure a smooth handover.
“Having overseen the group's digital operations for 18 months, he knows the business well and is ideally suited to lead our next phase of growth,” said chairman Roger Devlin.
“Ulrik has deep understanding in digital and has the international and sector experience we need to deliver on our strategy. His appointment will provide continuity, stability and operational digital leadership as we deliver on the strategy we have set."
Begntsson, who joined Hills in April last year, was previously chief executive of Swedish online gaming specialist Betsson.
Devlin said Bowcock has led the business through a period of “unprecedented change” including the challenges of the government’s triennial review into gaming machines and the group’s expansion in the US.
The government in April slashed maximum stakes on fixed-odds betting terminals from £100 to £2 after concluding they were linked to gambling addiction.
The regulatory change hurt William Hill’s first-half results with the company posting a loss of £63.5mln for the period. It took a £97mln one-off accounting charge related to the impact on the value of its bookmaking business
The firm would have reported a £51mln profit for the first half if not for the FOTB curbs, which prompted management to close 700 bookie shops.