The 84-year-old, once a much-loved artist and musician, was convicted by the jury of six men and six women at Southwark Crown Court of 12 charges of indecently assaulting young girls yesterday. The offences took place over two decades.
Harris' sexually assaulted four victims, some as young as seven or eight, between 1968 and 1986.
His became the biggest scalp claimed by detectives from the high-profile sex-crime investigation Operation Yewtree.
Dozens more alleged victims have come forward during the trial, including several in Australia. The NSPCC said it has received 28 calls relating to Harris to date, involving 13 people.
Harris was impassive as the jury forewoman delivered unanimous verdicts. He was freed on bail until he is sentenced on Friday.
His daughter Bindi, wife Alwen and niece Jenny watched from the public gallery as Justice Sweeney warned the 84-year-old that it was "inevitable" that a custodial sentence would be possible.
The judge told the jury: "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.
The court had heard from six witnesses who claimed they had been groped by Harris, but whose allegations were not part of the criminal charges.
The first claimed she was 11 or 12 in 1969 when at a family friend's home Harris allegedly hugged her and assaulted her.
A woman aged 16 or 17 was waitressing at an event in New Zealand in 1970 when she claimed Harris indecently assaulted her.
The third supporting witness was holidaying in Malta aged 18 in 1970 when her boyfriend cut his foot swimming in the sea.
Harris helped them find a doctor but she claimed that Harris then pinned her against a wall, before sexually assaulting her.
Jurors heard from a make-up artist who claimed Harris had groped her more than 24 times in a single day.
It was alleged the entertainer carried out the attacks while making a television programme in Australia in the mid-1980s.
The woman, then in her 20s, told the court she found out Harris's nickname was "the octopus".
Detective Chief Inspector Mick Orchard said: "Rolf Harris has habitually denied any wrongdoing, 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."
Jenny Hopkins, Deputy Chief Crown Prosecutor in London, said: "The victims in this case have suffered in silence for many years and have only recently found the courage to come forward."
Harris walked slowly from the court building with his wife, daughter and niece. His public relations team said he would not comment on the verdicts.
Harris could now lose his CBE. Honours are normally forfeited when a person brings the system into disrepute.The decision must be approved by the Queen, who once sat for a portrait by Harris.