The death of Dalian Atkinson caused great shock and sadness throughout the police force, Rachel Jones said.
Speaking after Constable Benjamin Monk was convicted of manslaughter, she said the police uniform should represent justice, public safety and the observance of the law.
She said the case had damaged trust and confidence in the police locally and nationally, particularly to black people, and caused grave concern within the police service.
A statement said: "Words alone cannot express the deep regret and shock I feel that I must stand here and address you because a West Mercia officer has been found to be criminally responsible for Dalian’s death.
"I am sincerely sorry and extend my apologies and deep condolences to Dalian’s family and friends. You have demonstrated great dignity and strength throughout.
"Dalian’s death has devastated his family, friends and local community. It has also caused great shock and sadness throughout the police service."
She said that police officers went to work to serve their communities and keep the public safe.
"Our uniform should represent justice, public safety and the observance of the law. Those who wear it, as individuals, are also subject to those laws and should be held to the very highest standards of conduct and behaviour. A police uniform does not grant officers immunity to behave unlawfully or to abuse the powers bestowed upon us by the public.
"On the night of August 15, 2016, Pc Ben Monk behaved in a way that has been found to have directly contributed to Dalian’s death, and he has been convicted as a result.
"We do not underestimate the impact of this case and the verdict. It is wide-reaching and immeasurable. Nor do we underestimate the significant damage that it has done to the trust and confidence in the police locally and nationally, particularly to Black people. It causes grave concern within the police service.
"We work hard to build and maintain the trust and confidence of the communities we serve. When something happens to harm that relationship, we must stop, listen and work with the public, particularly those communities where trust is fragile, to strengthen those bonds. We recognise there is much to do."
The Assistant Chief Constable said the process led by the Independent Office of Police Conduct was lengthy and complex.
"Whilst I acknowledge that it was delayed in part due to Covid, it has still taken nearly five years to complete, which has been an extremely long and difficult journey for all involved.
"The Independent Office of Police Conduct made a number of recommendations to us following Dalian’s death, including the introduction of Body-Worn Video and further training regarding Taser use. Those recommendations have been implemented. We will also continue to work with national colleagues to support and implement further change to ensure we continue to be in-line with best practice."
West Mercia Police is now undertaking a fast-track misconduct process.