Martin's earlier work on the Indian subcontinent led to him become Head of the Asia Region in the Research Department of Amnesty International in 1985.
[5] Martin headed Amnesty International missions to Israel and the Occupied Territories, Uganda, Bahrain, Kuwait, Republic of Korea, Argentina, Austria, Egypt, Bangladesh, Cuba, Philippines, Hungary, Mozambique, USSR, Syria, Pakistan, Sudan, Jordan, Yemen, Colombia, Peru, Bhutan, Kazakhstan, Kyrgyzstan, Uzbekistan, Tunisia and India.
[8] According to Hopgood, Martin's decision was partially due to conflict with the chairman of Amnesty's International Executive Committee, Peter Duffy.
[2][3][6] After leaving Haiti, Martin was named Chief of United Nations Human Rights Field Operation in Rwanda from 1995 to 1996.
[3][6][9] In October 2005, the government of King Gyanendra put in place a restrictive media ordinance which resulted in Martin's office releasing a statement decrying it as "violat[ing] international human rights standards".
[3][11][12][13] The Board's report, a summary of which was released on 5 May 2009, concluded that seven separate incidents were the result of firing by the Israeli Defence Forces, but found no evidence that U.N. facilities had been used to launch attacks against the IDF.
[14] The Board also recommended that the U.N. further investigate violations of international humanitarian law by those on both sides of the conflict: Israeli forces, Hamas, and other Palestinian militants.
[11] Martin was named Special Adviser to the Secretary-General on Post-Conflict Planning for Libya in April 2011 and was responsible for coordinating various agencies, funds, and programmes of the United Nations as well as consulting with the International Organization for Migration and the World Bank.
[3] Martin was the Special Representative of the Secretary-General and Head of the United Nations Support Mission in Libya from 11 September 2011 until 17 October 2012 when he was succeeded by Tarek Mitri.
[17] On 10 May 2012 Martin told the United Nations Security Council that there were credible reports of loyalists to toppled leader Muammar Gaddafi being mistreated and even tortured to death in detention centres under the transitional government's control.