Andrew Keenan had been with Cummins for 34 years.

After working his way up from a technical engineer apprenticeship in the UK to South Pacific and South East Asia regional leader, Keenan was making $198,200 a year in his role overseeing 60 employees when he was sacked in 2015.

While the official reason was performance issues, Keenan believed it was because he had complained about his employer.

He had endured a bad working relationship with the Cummins South Pacific and South East Asia HR leader ever since she started and made complaints that she was not willing to accept responsibility and often escalated issues prematurely.

When the HR leader got into a disagreement with another colleague and Keenan sided with the colleague she became enraged, which led to Keenan complaining to the global HR manager.

The global manager dismissed his concerns, however, saying the HR leader was just more touchy feely, with Keenan then questioned about his own management style.

The global HR department then told him in April 2015 that he was not good enough for his role and had six months to find another job within the company.

A month later the HR leader lodged an ethics case against him claiming he had failed as a leader.

He was then sacked in November and forced to make ends meet driving for Uber on just $15,000 a year.

The court found in favour of Keenan and ruled the sacking was in contravention of the Fair Work Act (2009).

Judge Joshua Wilson told Cummins it had its head in the sand for sacking a senior executive for exercising his right to complain, and ordered his reinstatement and payment of $1.1 million in back pay.

Once he returns to work Cummins will not be able to take any further action against him, making him virtually untouchable.

While Cummins argued it would be unfair to turf Keenan's replacement out of the job  and "inappropriate and embarrassing" to give him back a leadership role because of the unfavourable evidence that came out of the trial, this was rejected by the court.

According to the court: " It must not be overlooked that Mr Keenan's loss of employment was the consequence of the respondent's unlawful conduct.

"It ill behoves the respondent to mount an array of arguments to the effect that the respondent's own internal organisation of its own staff is such as to prevent the court from reinstating Mr Keenan to the position he would still occupy had the respondent not engaged in the prohibited conduct."