Major-General Robert Mood takes over a mission that faces major obstacles before the full 300-member force approved by the U.N. Security Council has even gathered. The unrest has killed more than 9,000 people since March of last year, according to UN figures.
The Local Co-ordination Committees (LCC), an opposition activist network, reported the deaths of 31 people on Saturday, including three children, amid anti-government protests across the country.
Five explosions were heard in Damascus on Friday, with the biggest in al-Midan district, in which a suicide bomber killed 11 people and injured dozens, including civilians and law-enforcement personnel.
A key part of a six-point peace plan laid out by international envoy Kofi Annan involves a cessation of violence by government forces and members of the opposition.
Syrian activists have been dismayed at the pace of the observer's deployment. A senior U.N. official said this week it would take a month to put the first 100 monitors on the ground, though the world body is working to speed up the pace.
The United States is not providing monitors, but is helping with funding and logistics.
Since the official announcement of his appointment, Major-General Mood has not made any comments to the media, but in a recent interview with a Norwegian newspaper he said the mission is "worth making the effort," because "the Syrian people deserve to have an opportunity."
Mood knows Damascus well - he was here to negotiate conditions for an advance team of UN observers, and was head of the U.N. Truce Supervision Organization (which monitors Middle East cease-fires) from 2009 until 2011.