PC Richard Wilby-Newton was dismissed from the South Yorkshire force after a misconduct panel found him guilty of gross misconduct.
PC Wilby-Newton originally denied he had kicked the man while he was handcuffed and on the ground, but in a later interview he accepted he had used force on the man, but was "unable to remember the event".
He did not accept that the force he used was inappropriate.
A South Yorkshire Police spokeswoman said: "PC Richard Wilby-Newton appeared at a misconduct hearing on October 14 and October 15.
The officer was alleged to have kicked a detainee while the detainee was handcuffed and on the ground. In an initial interview, the officer denied that he was the officer responsible for using force on the detainee. After further investigations, in a subsequent interview he accepted that he was the officer who had used the force on the detainee but was unable to remember the event. He did not accept that the use of force was inappropriate.
"The panel, chaired by a legally qualified chair, decided that the officer had used inappropriate force against the detainee and that his account in the initial interview was not an honest account . They found that both allegations were proved and the conduct amounted to gross misconduct. The officer was dismissed without notice. "