Early career Ilias signed a development contract with
Wests Tigers in 2017. In 2018, after a meeting with
Anthony Seibold, Ilias transferred to the
South Sydney Rabbitohs for the 2019 season.
2021 Ilias made his debut for
South Sydney at in his side's 20−16 victory over the
St. George Illawarra Dragons at
Sunshine Coast Stadium in round 25 of the
2021 NRL season, Ilias also scored a try on debut.
2022 In round 15 of the
2022 NRL season, Ilias was substituted shortly after half-time during South Sydney's 32-12 loss against
St. George Illawarra. South Sydney were down 32-0 at half-time, and Ilias had knocked the ball on from the opening kick off. Ilias played 26 games for South Sydney in the
2022 NRL season including all three of the clubs finals matches as they reached the preliminary final for a fifth straight season. Souths lost in the preliminary final to eventual premiers
Penrith 32-12. Ilias made his international debut for against on 17 October 2022 at the
2021 Rugby League World Cup.
2023 In round 4 of the
2023 NRL season, Ilias kicked a field goal during golden point extra-time to win the game for South Sydney over Manly 13-12. Ilias played a total of 24 games for Souths in the 2023 NRL season as the club finished 9th on the table and missed the finals.
2024 After South Sydney lost their opening two games of the
2024 NRL season, Ilias was demoted to reserve grade and replaced with
Dean Hawkins. In round 5 of the NSW Cup season, Ilias suffered a fractured tibia during South Sydney's match against the
New Zealand Warriors. It was announced that Ilias would miss a minimum of three months. On 29 April, it was announced by the South Sydney club that Ilias was free to negotiate with other teams at the end of the 2024 season. On 25 November 2024, Ilias signed a two-year deal with the
St. George Illawarra Dragons.
2025 In round 1 of the
2025 NRL season, Ilias made his club debut for St. George Illawarra against Canterbury which ended in a 28-22 loss. The following week, Ilias came under fire from head coach
Shane Flanagan following the clubs loss against his former side South Sydney. Flanagan said of Ilias “The people who needed to make the decisions didn't make them or the right ones and didn't get us into field position". Following the clubs heavy loss against the Sydney Roosters in round 8, Ilias was demoted to the clubs reserve grade side, despite putting Sloan through for a nice try late in the second half. Ilias was limited to seven appearances with St. George Illawarra in the 2025 NRL season - finishing with 3 wins and 4 losses including a major win against grand finalists
Melbourne Storm, as head coach Shane Flanagan opted to select his son Kyle ahead of Ilias as the preferred halfback option. St. George Illawarra would finish the season in 15th place, the red v were running 7th before Lachlans omission. Ilias led the St. George Illawarra
NSW Cup team to the 2025 Grand final at halfback. On 28 September, Ilias played in St. George Illawarra's 30-12 NSW Cup Grand Final loss to
New Zealand finishing with two assists. On 2 November, the
Gold Coast Titans announced that they had signed Ilias on a two year deal. == Statistics ==