Born in Galway, Leader grew up in Castlegar, just outside the city. He is a past pupil of the Bish, one of the city's secondary schools, and the Cistercian College in Roscrea. Leader is the older brother of current Connacht player Darragh Leader. Greg, the eldest brother, played for the province at underage level. Their parents were also heavily involved in sport, with their mother, Breda, serving as secretary for Rowing Ireland and their father, Noel, having played for and served as president of the Galwegians rugby club, where Leader first played the sport.
Club career
Connacht
Leader graduated secondary school and signed for the Connacht academy in 2011. Later that year, Leader played an integral role in the Connacht under-20 grand slam winning team. Leader was brought into the Connacht senior squad for the 2012–13 season. Leader went on to make multiple appearances for the Connacht Eagles in the British and Irish Cup. After multiple injury setbacks Leader left Connacht and signed with Italian club Rugby Badia ASD.
Rugby Badia ASD
Leader arrived in Italy to play with Rugby Badia ASD in Italy's Serie A rugby competition. A few months into his time in Italy a shoulder injury forced him to return to Ireland for surgery.
In 2015, whilst recovering from a shoulder reconstruction Leader received a rugby scholarship at Lindenwood University in St. Charles, Missouri to play for the school's college rugby side the Lindenwood Lions. During his time at Lindenwood, Leader pursued an undergraduate degree in sports management. Leader was selected to play in the Lindenwood team that represented the United States at the Red Bull World Uni 7's in Bath in England. However, shortly after arriving, Leader was ruled ineligible to represent the university in intercollegiate matches due to his time spent as a professional player in Ireland and Italy.
St. Louis Royals
Leader linked up with local club the St. Louis Royals in 2016, whilst continuing his studies at Lindenwood. As captain-coach Leader led the Royals to a DIII national championship in 2017. Leader was also named player's MVP of the Royals after the 2017 season.
In April 2011, Leader was selected for the Ireland under-19 squad for their game against France. Later that year in December 2011, Leader was selected as part of Mike Ruddock's squad for the Ireland under-20s in preparation for the 2012 under-20 Six Nations tournament. Having lived in the United States since 2015, under the World Rugby three-year residency rule, Leader became eligible in 2018 to play for the United States. Leader was called up to the U.S. squad for the 2019 Americas Rugby Championship.
