The riot squad officer caught on camera pushing Ian Tomlinson to the ground before his death will face disciplinary proceedings for gross misconduct.
Pc Simon Harwood, a member of Scotland Yard’s territorial support group, escaped prosecution last week over the incident on the fringes of G20 protests last year.
However, Paul Stephenson said the officer has been informed he will face a disciplinary hearing after the force received an independent report into the clash.
Stephenson told a meeting of the Commons Home Affairs Committee he was “disturbed” by the amateur video footage of Mr Tomlinson being hit with a baton and pushed over.
He said: “I can confirm that the officer has been notified that a decision has been made to bring disciplinary proceedings for gross misconduct.”
Stephenson added: “It is right we move swiftly and it is also right that there is full public disclosure at the inquest.”
The senior officer said it would be “entirely inappropriate” to comment on the Crown Prosecution Service’s decision not to prosecute last Thursday.
He said the incident has “cast a shadow” on the professionalism of the “overwhelming” number of officers and staff involved in policing G20.
Stephenson said: “I do fully understand the Tomlinson family and public sense of anger, having seen the video of the incident prior to the death of Ian Tomlinson.
“I do understand the level of outrage that this did not lead to a criminal prosecution, I can sense it and I can feel it.”
Pc Harwood was filmed striking the 47-year-old newspaper seller with his baton and pushing him to the ground in the City on April 1 last year.
Director of Public Prosecutions Keir Starmer said there was “no realistic prospect” of a conviction after a 15-month inquiry because of “irreconcilable” differences between medical experts.
Mr Tomlinson’s family accused the authorities of a cover-up and instructed their legal team to review the decision ahead of an inquest into his death.