2 Sisters, headed by so-called "chicken king" Ranjit Boparan, bought the firm from private equity group Rutland Partners through a pre-pack administration.
A spokesman for Mr Boparan said: "We intend to respect and build on the 66-year heritage of a much-loved British brand and crucially help to deliver Christmas 2016, which would have been at risk without our intervention.
"We have a proven track record in turning around businesses and we aim to make Bernard Matthews great again."
The deal does not include the Bernard Matthews pension scheme, which is likely to fall into the Pension Protection Fund.
Bernard Matthews, which has been loss-making for several years, has operations in Norfolk and Suffolk.
Rutland said in a statement: "We have invested significant funds into the Bernard Matthews business and brand over the last three years in a continually challenging market.
"Whilst disappointed that the business has continued to struggle during our ownership, we are pleased that it has now been acquired by Ranjit Boparan with access to a large UK poultry group and that all the jobs have been preserved."
2 Sisters, which also owns the Fox's Biscuits and Goodfella's pizza brands, supplies a third of poultry consumed in the UK, earning Mr Boparan the nickname "chicken king".
Unite regional officer Steve Harley said: "The announcement that Bernard Matthews has been sold by its owners Rutland Partners to the 2 Sisters Food Group appears to be good news for the 2,000-strong workforce. We are giving the news a cautious welcome."
However, Unite the union said it is seeking further clarification over terms and conditions, pay, and pensions, under the new owners.
Unite says it is due to meet the management of Bernard Matthews at its headquarters in Great Witchingham, Norfolk.
The union represents around 800 Bernard Matthews workers at production sites including Great Witchingham, Holton and Bawsey.
"Bernard Matthews is a major employer in East Anglia and the union wants to work constructively with the new ownership to ensure the continuing success of this iconic company," Mr Harley said.