"Quick, powerful and really keen to learn, he has earned his place in this team and I look forward to seeing him in action in Dubai."
"I'm really excited about this new adventure with the Aussie 7s," Williams said in May after signing a contract with Rugby Australia through until 2021.
"I've always loved rugby and to be able to potentially chase an Olympic dream through rugby is something I never expected. I want to grab this opportunity with both hands."
Williams played schoolboy rugby and rugby league in Brisbane and attended academy training sessions with NRL club North Queensland in 2014.
Australia have been drawn in pool B at next weekend's season opener in Dubai alongside Scotland, USA and Ireland.
New Zealand are in pool C with Wales, Canada and Samoa.
The World Sevens Series will be available on Sky Sport.
Dubai Sevens groups
Group A
France, Argentina, Fiji, Japan
Group B
USA, Ireland, Australia, Scotland
Group C
New Zealand, Wales, Samoa, Canada
Group D
South Africa, England, Spain, Kenya.