Azziman started out by studying law in Rabat and Paris, going on to obtain his PhD in law at the University of Nice Sophia Antipolis. Since 1972 he has been Professor at the Faculty of Law at the Mohammed V University in Rabat.
Between 1993 and 1995 he was Minister Delegate to the Prime Minister for Human Rights in the Lamrani and Filali governments. He was appointed Minister of Justice between 1997 and 2002 in the Filali and Youssoufi governments. In April 1998, Azziman launched a highly publicized investigation of some 60 magistrates accused of corruption and sent their cases for review to the Conseil Supérieur de la Magistrature (Higher Judicial Council, or HJC).
Since 1996 he has been in charge of the UNESCO Chair for teaching, training and research in the field of human rights at the Mohammed V University. He has also served as advisor and expert to various governmental, non-governmental and international organisations.
He is a founding member of several human rights NGOs, including the Moroccan Organization for Human Rights (Organisation marocaine des droits humains - OMDH), of which he was the founding president.
He has represented Morocco at the annual sessions of the United Nations Commission on International Trade Law (UNCITRAL).
He is a member of the Academy of the Kingdom of Morocco since 1996 and since 1997 has been Deputy President of the Hassan II Foundation for Moroccans resident abroad since 1997.
On 10 December 2002, he was appointed Chairman of the Advisory Council on Human Rights by King Mohammed VI.
On 22 November 2004, the King appointed him Ambassador to Spain.
In March 2007, he was named an honorary member of the Carlos III Foundation in recognition of his contribution to the agreement between Morocco and Spain.
On 3 January 2010, the King appointed him Chairman of the Advisory Committee on Regionalization (CCR). 
In 1995, Mohammed VI decorated Azziman with the Order of the Throne. Since then he has received several other decorations: Grand Cordon of the Order of Merit (Republic of Portugal, 1988), Commander of the Order of the Legion of Honour (French Republic, 1999) and Grand Cross of the Order of Civil Merit (Kingdom of Spain, 2000) and Order of Ouissam Alaouite (Kingdom of Morocco, 2006). 
He is the author of two books, neither of which seem to have been translated into English
- Droit civil, droit des obligations, 1996
- La profession libérale au Maroc (Collection de la Faculté des sciences juridiques, économiques et sociales / Université Mohammed V. série de langue française), 1980
- "HM the King appoints Omar Azziman head of new Advisory Committee on Regionalization". MAP - Agenge marocaine de presse. 2010-12-09. Retrieved 2013-10-01.
- "HM The King Appoints Omar Azziman His Advisor". Morocco tomorrow. 2011-11-29. Retrieved 2013-10-01.
- "HM The King Appoints Omar Azziman His Advisor". Maghreb News. 2011-11-29. Retrieved 2013-10-01.
- "HM The King Appoints Professor Omar Azziman President-Delegate Of Higher Council For Education". Maroc.ma. 2013-08-20. Retrieved 2013-10-01.
- "King of Morocco Prioritizes Education Reform". 2013-09-03. Retrieved 2013-10-01.
- "Brief biographic note of Mr. Omar AZZIMAN". Arab Center for the Development of the Rule of Law and Integrity (ACRLI). September 2006. Retrieved 2013-10-02.