Greene King paid departing chief executive Rooney Anand £850,000 to prevent him taking positions with its rivals or offering jobs to key staff.
However, in the group's annual report, it said his 2004 contract terms were "inadequate" to protect the company from him joining competitors or poaching Greene King employees. Anand has been credited with transforming the regional brewer and pub business into one of the UK's leading pub companies.
Anand agreed to restrictions including, for the 12 months after his termination date, not taking on an executive or non-executive position with 18 named competitors.
The group said it was "vital" for Greene King to secure such protections, as "he is not retiring on stepping down from the company" and "could have chosen to remain active as an executive within our industry".
Anand's contract also permitted him to leave on six months' notice, which Greene King said would have left the company "exposed", given that any successor from outside the company would likely not be available until the end of their own notice period.
The payment in May, broadly equivalent to one year's fixed pay, is described as "proportionate compensation for Anand delaying his potential departure to ensure a smooth transition and agreeing not to join named key competitors".
Anand was replaced by Nick Mackenzie from Merlin Entertainments earlier this year, and the group reported stable pre-tax profits (adjusted) of £246.9m in June, an increase of 1.6% on the previous year.