General Stanley McChrystal, who was fired last week as the top US general in the Afghanistan war, told the Army he will retire.
Army spokesman Colonel Tom Collins said that Gen McChrystal notified the service of his plans.
The general submitted formal retirement papers, but it is not clear when he will leave the service because the process usually take a few months.
In announcing Gen McChrystal's ousting on Wednesday, President Barack Obama praised his long Army career but said his intemperate remarks in a magazine article that appeared last week could not be abided.
Gen McChrystal apologised for the remarks in Rolling Stone magazine and flew to Washington last week to resign as commanding general of the war.