[4] He played more than 300 games for Randwick, winning the Shute Shield seven times during a period when the Galloping Greens dominated Sydney rugby.

[citation needed] Cheika's second season in charge was a difficult one, as Leinster were knocked out of the Heineken Cup at the quarterfinal stage by London Wasps.

In an all Irish derby at Croke Park against defending champions Munster, Cheika guided the team to a historic 25–6 victory to set up a final against Leicester Tigers.

[11] In his final season in charge, Cheika led Leinster to top of the table in the revamped 2009–10 Celtic League, with 13 victories from 18 starts.

Cheika left his post with Leinster Rugby at the end of that season to become head coach for French Top 14 side Stade Français.

Cheika's team beat Clermont, who had dropped down from the Heineken Cup, by 29–25 in the semifinal, but narrowly lost to Harlequins 19–18 in the final at Cardiff.

He was responsible for signing Israel Folau from AFL side Greater Western Sydney Giants, who made a massive impact to the Wallabies in his debut season.

[citation needed] Cheika secured further key signings for the 2014 season including Kurtley Beale, Nick Phipps, Jacques Potgieter and another Rugby League convert Taqele Naiyaravoro.

He created attacking backline combinations with Phipps and Bernard Foley as the halves, Beale and Adam Ashley-Cooper in midfield and with Folau at fullback.

In just his second season in charge, Cheika coached the Waratahs to their first ever Super Rugby title, with the team finishing seven points ahead of their nearest rivals, the Crusaders.

It was a surprise for some how well the Waratahs did, considering the team had to play for 10 consecutive weeks between their second bye and the knock out stage, which included their two away matches against South Africa opposition.

[citation needed] Cheika was appointed as the head coach of the Australia national team on 22 October 2014, with a three-year contract that would see him take the Wallabies through the 2015 Rugby World Cup.

[14] Cheika took over after Ewen McKenzie's shock resignation the previous week and had very little time with the team before Australia started their 2014 end of year tour.

Cheika made it clear that the scrum needed to be fixed before the World Cup, and later sacked the forwards coach Andrew Blades.

[citation needed] Scrum coach Mario Ledesma was recruited to the Waratahs and began working on scrummaging with the Wallabies players that were in New South Wales.

[17] In the lead up to the 2015 World Cup, Cheika is credited for inventing Giteau's law which enabled overseas based players to play for Australia.

It wasn't until the last round of the Championship that Cheika retained the previous starting XV in two consecutive matches, for the first time in his Career as Wallabies head coach.

The Wallabies endured a shocking run in 2018; in June, Cheika led the team to a series defeat against Ireland, losing 2–1 having won the first test 18–9.

This meant the Wallabies dropped to a record low seventh place on the World Rugby Rankings and, after Round 5, their woes continued as they lost to South Africa 23–12.

Cheika's team endured a similarly dismal run in the 2018 autumn internationals, losing 9–6 to Wales (their first win over Australia since 2008) before salvaging a consolation 26–7 victory against Italy.

A review of the team's performance was conducted by the administration of Rugby Australia, with the board electing to back Cheika through to the 2019 World Cup.

The decision was widely derided in the Australian sporting press, with speculation rife that the administration were unable to afford to terminate Cheika's contract.

At the 2019 Rugby World Cup Australia won three of their four pool matches but a close loss to Wales led to a quarter-final fixture with England.

Similar to their first round encounter, Los Pumas started the match in a rapid fashion, scoring four tries in just a half-hour of play, and lead Australia by sixteen points at half-time (26–10).

[38] A snappy reply from Australia's Len Ikitau saw them reduce the lead back to fourteen-points by the seventieth minute with only fourteen players on the field.

[63] On 2 October 2024, he was given two-week ban, with one week suspended, by the Rugby Football Union after being found guilty of "disrespecting" a match-day doctor during his first game in charge of Leicester.

[66] In September 2020, the Argentine Rugby Union (UAR) announced that Cheika had joined the team prior to the 2020 Tri Nations Series, taking up an advisory role and re-joining former Wallabies coaching staff, Mario Ledesma.

[67] In November 2020, Cheika was appointed head coach for Lebanon, the country of his parents' birth, ahead of the 2021 Rugby League World Cup.

[72][73] The 2021 Rugby League World Cup was postponed to October and November 2022 and coincided with Argentina's 2022 Autumn International tour of Great Britain.

[84][85] He was known among the Leinster rugby fraternity as Mic Check 1–2,[86] a humorous allusion to his name, Craig McLachlan's band and his eagerness that all facets of preparation were scrutinised and reviewed prior to matchday.