Georgallis made his début with the Roosters in 1989 playing. Over the 4 seasons with the club he had spells playing as a and without being able to cement a position, making only 38 appearances. Joining the Magpies in 1993, he proved just as adaptable, and was a cornerstone of the team for 7 seasons, playing in 148 games. During this time he also spent an off-season in England playing for Wakefield Trinity. By 1999, Georgallis had started making appearances as a, and was captaining the struggling Magpies. He played a season mostly from the bench for the Wests Tigers after the merger with Balmain. He was cheered from the field at the completion of his last Australian game. In 2001, Georgallis joined the Warrington Wolves for a season. Wolves' coach Darryl van der Velde said at the time, "He knows what Rugby League's all about. He is very strong, has good hands and is always busy on the field." Unfortunately, Georgallis only lasted 6 games before the end of his professional career, though he did make later appearances as captain of Greece.
Coaching
In 2008 Georgallis was the coach of the Penrith Panthers' National Youth Competition under-20s team. He has also coached the Greece national rugby league team. Georgallis coached Greece in the 2009 Australian Mediterranean Shield. Greece won the final 34-14 against Italy. On 20 June 2011, it was announced Georgallis would take over as interim Penrith Panthers coach following the resignation of Matthew Elliott. He had success immediately with the Panthers winning 30-20 Against the North Queensland Cowboys. Georgallis had won his first two games as coach when it was announced that Phil Gould had chosen Ivan Cleary to be the Panthers coach from 2012 onwards. The Panthers won just two of the remaining nine games of the season. Despite seeking other positions as head coach, such as the vacant position at Canterbury-Bankstown, Georgallis came to be an assistant coach at the Wests Tigers in 2012. Georgallis coached the Greece national rugby league team to a 90-0 victory over Hungary in Budapest on 27 October 2013. Georgallis was named the NSW Cup Head Coach of the Canterbury Bankstown Bulldogs for the 2017 season. Georgallis led the side to a top 4 finish and a finals appearance. It was later announced that Georgallis was appointed as an Assistant to first grade coach Dean Pay for the 2018 NRL Season however, he would also continue in his role as coach of the NSW Cup side. In 2018, Georgallis guided the Canterbury reserve grade side to the Intrust Super Premiership NSW and the NRL State Championship. He was later promoted to Canterbury Bankstown Bulldogs NRL Assistant Coach for the 2019 NRL season on a full-time basis. Following the Bulldogs loss to the Brisbane Broncos in Round 9, 2020 and the uncertainty about his future, along with media speculation about the Bulldogs being interested in a new coach from 2021, Dean Pay resigned from his position as head coach of the Bulldogs. Georgallis was named as the club's head coach for the remainder of the 2020 season.
