Hirini was part of the New Zealand team which won gold at the Tokyo Games three years ago, but had been sidelined since damaging her cruciate ligament at the Dubai Sevens in December.
The 31-year-old forward has recovered to win selection for her third Olympics, having also earned silver when the Black Ferns lost the 2016 final to Australia in Rio de Janeiro.
"We sat down six months ago and knew that it was achievable, but it would be tight," New Zealand coach Cory Sweeney said.
"It's been pretty unbelievable seeing how hard she has worked to get back and we will really ramp up her involvement over the next six weeks."
Hirini was a New Zealand flag-bearer at the opening ceremony for the Tokyo Olympics alongside boxer David Nyika.
She joins Portia Woodman-Wickliffe, Theresa Setefano and Tyla King, who were also named in the squad for Paris, having likewise won medals at the last two summer Games.
Hirini has also excelled for New Zealand's 15-a-side team and was part of the side which won the Rugby World Cup in 2017 and 2022.
She also won Commonwealth Games gold in 2022.
