Garrioch joined the
Colonial Service in 1936 and was subsequently appointed a First Grade Clerk in 1946, when he was picked to be a judge's secretary. He became the secretary of Justice
Georges Espitalier-Noël, who was able to persuade Chief Justice Sir
Francis Herchenroder that Garrioch should be encouraged to embrace a legal career. Garrioch took the advice and won the Colonial Scholarship enabling him to complete his studies in law in the United Kingdom. He was called to the Bar at
Gray's Inn and to the
Mauritian Bar in 1952. On his return to Mauritius, Garrioch was immediately appointed to the post of Crown counsel, at a time in the 1950s when it was the chief justice who advised the governor on the appointment of Law Officers and District Magistrates. 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. He was made a judge of the
Supreme Court in 1967. == Mauritian constitution and role in independence ==