Sergeant Delroy Smellie, 47, was reinstated by the Metropolitan Police within hours of walking free from court in March.
A district judge found he was justified in hitting animal rights activist Nicola Fisher during clashes outside the Bank of England on April 2 last year.
But the trial highlighted how he was not wearing identification numerals and had been working for 28 hours with only a three-hour break.
The Independent Police Complaints Commission (IPCC) today published its final report into the controversial incident.
Officials said senior officers agreed with their recommendation that there was no misconduct case to answer.
But they recommended that the Met ensured officers wore identification at all times and reviewed their shift patterns to make sure public order officers get a break.
Deborah Glass, of the IPCC, said: "Now that proceedings are concluded, we are publishing our final report.
"Most of the detail is already in the public domain as a result of Sergeant Smellie's trial, but, given the public interest in the case, I believe it is important to ensure there is a public record of the investigation and our findings."
Sgt Smellie has become a figure of hate for many demonstrators who have already published internet pictures of him back on the front line.
The officer, a member of the force's controversial Territorial Support Group, was accused of beating Miss Fisher.
But a judge ruled there was no evidence that his use of the extendable weapon to defend himself was unreasonable in the circumstances.
Amateur video footage of Sgt Smellie clashing with Miss Fisher was watched around the world after it was posted on YouTube.
The incident took place on the fringe of a heated demonstration to mark the death of Ian Tomlinson.
The footage showed the officer pushing her, roaring at her to go away, hitting her with the back of his hand and eventually striking her twice with the baton.
Prosecutors said all the officer's actions were justified, except the baton strikes, which went too far.
But Sgt Smellie argued that he feared for his safety and that of his colleagues after being caught behind the backs of a line of officers.
Miss Fisher, who sold her story for £26,000, said she was "disappointed" with the result of the four-day trial, which she did not attend due to illness.
A Metropolitan Police spokesman said changes had already been made to kit and procedures to ensure officers were wearing identification.
He said senior officers were "extremely careful" to ensure staff received sufficient rest but G20 was an "exceptional and challenging event".
The spokesman said: "Sergeant Smellie was found not guilty of common assault, the magistrate finding that the force he used was proportionate in the context of an extremely challenging policing environment.
"Officers are trained to act in fast-moving situations, making split-second decisions to protect themselves, colleagues and members of the public.
"Every officer is accountable for their actions and is fully aware that whatever action they take may be subject to scrutiny. Neither the Met or individual officers expect, or want, this to be any other way.
"The Met takes any suggestion that officers or staff have not met the professional standards expected of them very seriously.
"It is only right that complaints are thoroughly, and where appropriate independently, investigated so facts can be established. This is vital for the confidence of Londoners as well as our own officers.
"The officer was returned to duty in light of the verdict and, following the IPCC view that there was no further case to answer, the officer will not face misconduct proceedings."
The IPCC also dismissed a second complaint against Sgt Smellie following an incident in Great St Helen's, off Bishopsgate, on April 1.
A woman came forward after the Bank of England protest footage was broadcast to complain about the actions of the officer.
Officials said Sgt Smellie accepted pulling the woman back and that she fell to the ground, but was not injured.
Mrs Glass said the woman was seen trying to release some police cordon tape as officers attempted to contain a crowd.
She said: "The use of force was therefore reasonable in the circumstances. I find no case to answer in relation to this complaint."
