That form brought him into the national side for a home T20I series against Sri Lanka. The selectors picked a squad short on experience for those matches, since the senior players were getting ready for a tour of India. When he made his international debut, Richardson had only one first-class appearance to his name. He played in two T20Is during the series without making a significant impact.
He opened the 2017-18 season in good touch and then produced another strong BBL campaign. Those performances earned him a place in the squad for Australia's home ODI series against England, and he was given his debut in the format. Observers rated the outing as fairly promising, with Richardson generating good pace and striking the bat with force.
Richardson was included in Australia's squad for the 2019 Cricket World Cup, but a dislocated shoulder did not heal in time and he was unable to take part. He later featured in the home squad for the 2021/22 Ashes, and in the second Test, played at Adelaide, he claimed the first five-wicket haul of his career.