The beatific female with flowers in her hair is the largest art mural ever seen in Sydney. American artist Shepard Fairey calls her "The Peace Waratah". "The waratah is really beautiful but it's also really hardy, it helps people get through times of struggle," he says. "Right now, with what's going on in a lot of places in the world, I thought that was very appropriate."

He likes lotuses but chose NSW's floral emblem to feature in his first public mural in Australia. "I am not above pandering."

His Vivid Sydney artwork is 44 metres high and 28 metres wide, spread across the side of an office block at 309 George Street. The mural will require about 400 cans of spray paint, in aqua, blue and cream. Fairey expects to be finished by June 17, in time for his appearance at the Vivid Ideas Game-Changer talk series.

His brief was to create something "apolitical and positive", which he is happy to do. The artist - best known for his iconic "Hope" poster of former US President Barack Obama - wants to spread some peace and harmony.

"Right now, with what's going on in a lot of places in the world, there is a lot of friction. The idea that we can be resilient and peaceful is something I would like to convey."

Fairey isn't so airy-fairy. The 47-year-old wears a black hoody with the slogan "Minor threat". His Black Sabbath T-shirt is paint-splotched, his fingernails gnawed.

He still dabbles in "street bombing" - unlawfully pasting and painting cityscapes with subversive imagery. He's been arrested 18 times for clandestine artworks - suggesting he's been either quite prolific or quite poor at evading police.

He won't say whether he will do anything shady in Sydney. "I have learned that it's better not to talk about that."

Before spreading the message of "Hope", he famously paired the leaden gaze of professional wrestler Andre the Giant with the Orwellian command "Obey".

But then Fairey had children and things changed. "I realised what it takes to be a father, a parent, a role model, and to try to look at ways to have a positive impact on my own kids."

His two daughters are now aged 12 and nine. The Peace Waratah mural also says "Obey" but in an optimistic kind of way.

"Obey the peaceful side of things," he says. "There's a lot of positivity to how people can support each other."

In late 2007, Fairey rendered a presidential hopeful in red, white and blue. A decade later, under an orange-painted president, the artist hasn't lost faith in the future.

"I always have hope, no matter how dark things look, because without hope you are really paralysed," he says. "Sometimes, I think that it takes a really tough situation for people to understand how important it is to be engaged."

Shepard Fairey will give a Vivid Ideas Game-Changer talk at Sydney Town Hall on June 17.

Printed Matters, an exhibition of Shepard Fairey's work, is at The Old Rum Store, Chippendale, from June 17 to July 9