He was a national treasure in the UK and Australia, loved and adored by children and adults alike, and even invited to paint the Queen’s portrait.

But Rolf Harris will now be remembered for a stunning fall from grace that’s resulted in the 84-year-old being convicted of indecently assaulting four girls in the UK between 1968 and 1986.

He’ll likely be jailed on Friday.

• Rolf Harris found guilty of indecent assault
• Harris now Yewtree’s biggest scalp 

A master of almost every medium and endlessly ingenious, Harris combined high talent with exuberant and almost palpable goodwill that made him a favourite of all ages for more than 50 years.

A few years after shooting to fame with his wobble board and nonsensical songs about kangaroos and a man called Jake who had an extra leg, he presented a show in which he would paint on stage in an apparent haphazard manner.

He would slowly reveal what he had painted, as he repeated the catchphrase: “Can you tell what it is yet?”

But perhaps the most revealing brushstrokes about Harris himself came as he was tried, and then convicted, of assaulting four girls, one as young as seven or eight.

Another six women gave supporting evidence during his eight-week London trial that the artist abused them in Australia, New Zealand and Malta.

Prosecutor Sasha Wass QC said indecent assault cases often relied on the word of one alleged victim against a perpetrator but with Harris many women had described his “deviant sexual behaviour”.

Harris was, she said, “a sinister pervert who had a demon lurking beneath the charming exterior”.

On Monday, a jury unanimously agreed, convicting the Australian on all 12 indecent assault charges.

Harris was born in Perth on March 30, 1930. His parents were Welsh migrants and his grandfather George Harris was a noted portrait painter.

He went to Perth Modern School, where a contemporary was Bob Hawke. He was already a competent pianist and artist – and swimmer. He was a state champion at several distances and narrowly missed selection for the 1952 Olympics.

Harris has written that he had a happy childhood growing up in Western Australia.

“There were always pencils and paper at home and drawing came naturally to me.

“I struggled at university. After two years I left and enrolled in teacher training college which I loved. My first job was perfect, teaching children to swim, but then something happened that changed everything.”

During a month’s hospitalisation – when he was “totally paralysed” and thought he had polio – Harris reflected on his life plans and decided to take a year off teaching to focus on painting.

At the age of 22, he headed to London, a city his parents had described as “the hub of the universe” with the best of everything, where he would study art at the City and Guilds Art School.

He broke into television, despite an audition which he described as a “disaster”, drawing cartoons with a puppet called Fuzz. Soon he was appearing on the BBC and in commercial television.

Every Thursday night, he and his piano accordion entertained homesick Australians at the Down Under Club, where he first sang Tie Me Kangaroo Down Sport.

He also customised the song, with lines like “Don’t ill-treat me pet dingo, Ringo” for a special performance with the Beatles.

The wobble board was discovered accidentally. To prepare for a portrait, he’d covered a sheet of masonite in oil paint. When he shook it, a “marvellous sound”, a sort of semi-liquid whoop-whoop, came out.

In 1969 he recorded the moving battlefield song Two Little Boys which went to the top of the charts and was said to be Margaret Thatcher’s favourite. A much later hit was his version of Stairway to Heaven.

He regularly returned to Australia, producing shows such as Rolf’s Walkabout, the ABC’s first Australian-made colour television series.

Harris starred in the first performance at the Sydney Opera House’s concert hall, appeared at the opening of the Brisbane Commonwealth Games with, “Let me welcome you to the games, friend”, helped initiate the Schools Spectacular at the Sydney Entertainment Centre, and recorded with the Adelaide Symphony Orchestra the Young Person’s Guide to the Orchestra, complete with Tubby the Tuba and Pee Wee the Piccolo.

For 10 years from 1994 he hosted the BBC’s Animal Hospital, which five times was voted Britain’s most popular factual entertainment show. A key to its success was Harris being able to show with great tenderness the close bonds between people and their pets.

That was followed by his Rolf on Art, in which he painted on camera in the style of such masters as Rembrandt, Picasso, Monet and van Gogh.

It was the most watched arts program in British television history.

In 1993, Harris became an unlikely headline act at the iconic Glastonbury music festival on the back of a rendition of Stairway to Heaven which he had covered a few years earlier.

Harris and his wobble board went on to appear at Glastonbury several more times.

But in late 2012 Harris was caught up in Operation Yewtree, a police investigation started after sex abuse allegations against the late BBC entertainer Jimmy Savile.

Harris is due to be sentenced on Friday but has already been told by Justice Nigel Sweeney to expect a prison term.

– with AAP