The New Zealand-born back will line up for his adopted country against Fiji in Catania on Sunday morning (NZT).
Hayward moved to Benetton Treviso in 2014 and qualifies for Italy through residency.
He made the switch from the midfield to fullback at that time too, where he will play this weekend.
Born in Hawera, the 30-year-old made 58 appearances for Taranaki, while also playing 48 Super Rugby matches for the Highlanders, Hurricanes and Force.
He played for the Highlanders in 2009 and 2010.
Italy: Jayden Hayward, Leonardo Sarto, Tommaso Boni, Tomasso Castello, Mattia Bellini, Carlo Canna, Marcello Violi, Sergio Parisse (captain), Abraham Steyn, Francesco Minto, Dean Budd, Marco Fuser, Simone Ferrari, Luca Bigi, Andrea Lovotti. Reserves: Leonardo Ghiraldini, Federico Zani, Dario Chistolini, Marco Lazzaroni, Giovanni Licara, Edoardo Gori, Ian McKinley, Matteo Minozzi.