The former England manager reached the legal maximum of 12 penalty points on his licence when he was clocked travelling at 57.6km/h in a 48km/h zone on August 27, 2008.
That was the week before the 57-year-old left Newcastle in acrimonious circumstances and the court heard that "his head was in turmoil" after a stressful meeting with club owner Mike Ashley.
Magistrates have the power to waive a ban for motorists who reach 12 points if it would cause exceptional hardship but Keegan, in a written submission, accepted he could not make such a case. As well as his ban, Keegan was fined £750.