The 84-year-old was convicted at Southwark Crown Court on Monday after being accused of 12 indecent assaults on four women between 1968 and 1986, all of which he denied.
Harris was released on bail until Friday when he will be sentenced.
Justice Sweeney warned him given the conviction on all 12 counts it was "inevitable" that a custodial sentence would be possible.
"He must understand that", he said, to which Harris's barrister Sonia Woodley replied: "He does appreciate that".
The judge told the jury: "During the case you will have had to grapple with a side of life which I suspect you would prefer not to have had to grapple with.
"You have done so in the face of daily attention of large numbers of members of the media representing the public and observation of how you have conducted yourselves."
He excused them from jury service for 10 years.
It has been reported dozens more alleged victims have come forward during the trial, including several in Australia, and Scotland Yard has been in touch with their counterparts in the Australian police.
It is not yet clear whether they are pursuing any investigation in Harris's home country.
The NSPCC said it has received 28 calls relating to Harris to date, involving 13 people who claim they fell prey to the performer.
I want to thank the women who came forward for their bravery, I hope today's guilty verdict will give them closure and help them to begin to move on with their lives.
DCI Mick Orchard
Once seen as a UK national treasure, Harris had enjoyed years of success, netting him a multi-million pound fortune and the chance to paint the Queen.
He has become the biggest celebrity scalp to be claimed by detectives from high-profile sex crime investigation Operation Yewtree.
Harris is the second person to be convicted under the national inquiry, which was set up in the wake of abuse claims against Jimmy Savile.
Police were contacted by one alleged victim, named in seven of the 12 charges that Harris faced, after she heard the claims made about late DJ Savile and gained the confidence to come forward in November 2012.
The other three then contacted officers - two in the UK and one in Australia - after UK newspaper The Sun publicly named Harris as a Yewtree suspect for the first time on April 18 last year.
During the trial, the court also heard from six other witnesses who claimed they had been groped by Harris, but were not part of the criminal charges.
The first claimed she was 11 or 12 when she was off sick from school at a family friend's home in 1969, when Harris told her "I want to be the first person to introduce you to a tongue kiss".
He then allegedly got her in "a gentle hug" before sticking his tongue into her mouth.
Jurors also heard from a make-up artist who claimed Harris had groped her more than "two dozen" times in a single day.
It was alleged that the entertainer repeatedly put his hands inside the freelancer's baggy denim shorts as far as her hips while making a television programme in Australia in the mid-1980s.
I hope today's verdict provides other victims with the courage and confidence to come forward no matter who is alleged to have carried out the abuse and when.
Jenny Hopkins, Deputy Chief Crown Prosecutor for the CPS
The woman, then in her 20s, told the court that she later found out Harris's nickname was "the octopus".
Speaking outside court, DCI Mick Orchard, said: "Rolf Harris has habitually denied any wrong doing forcing his victims to recount their ordeal in public.
"He committed many offences in plain sight of people as he thought his celebrity status placed him above the law.
"Today's case and verdict once again shows that we will always listen to, and investigate allegations regardless of the time frame or those involved."
Jenny Hopkins, Deputy Chief Crown Prosecutor for the CPS in London, said: "Rolf Harris used his status and position as a world famous children's entertainer to sexually assault young girls over a period spanning 18 years.
"The victims in this case have suffered in silence for many years and have only recently found the courage to come forward. I would like to pay tribute to the bravery they displayed in coming to court and giving evidence. That bravery and determination has seen Rolf Harris brought to justice and held to account.
"Each victim, unknown to the others, described a similar pattern of behaviour; that of a man acting without fear of the consequences.
"The prosecution of sexual offences is often difficult and complex, perhaps even more so when the allegations are from some years ago. We will continue to consider cases and wherever there is sufficient evidence and it is in the public interest, we will work with police and victims to build strong cases which can be put before a court."