Speaking outside a police building in Earl's Court, north London, she said: "Today's hearing has resulted in the maximum penalty that was ever available to the panel. Dismissal due to gross misconduct.
"This leave no ambiguity into how the Met views the action of Simon Harwood."
The 45-year-old had admitted striking Mr Tomlinson with his baton and pushing him to the ground during the riots near the Royal Exchange Buildings in the City of London on April 1 2009.
But he denied that his actions contributed to Mr Tomlinson's death and was cleared of manslaughter at a criminal trial in July.
Today a police panel found that he had breached professional standards through discreditable conduct and use of force, constituting gross misconduct.