Garrioch took the advice and won the Colonial Scholarship enabling him to complete his studies in law in the United Kingdom.
The established practice at that time was that members of the bar who were to join the public service had to first be appointed district magistrates; only those thought to be of the highest caliber were then transferred to the Attorney-general's Office.
Garrioch moved up in the office to become Director of Public Prosecutions, which at the time was higher in the legal hierarchy than solicitor-general.
The Mauritian authorities selected Garrioch, who spent several weeks at Le Réduit to finalize the draft before it went to Her Majesty in Council.
Following Sir Maurice Latour-Adrien's retirement Henry Garrioch was appointed Chief Judge of Mauritius on 20 April 1977 at the age of 61.