He also appears regularly on the evening broadcast NBC Nightly News, and fills in as an anchor on MSNBC.

[3] Simmons's first job in journalism was as a court reporter covering murders and scandals in London at the Old Bailey.

While at ITV, Simmons reported on major domestic and international stories including the 2004 Indian Ocean earthquake and tsunami, the 2008 Mumbai attacks, the poisoning of Alexander Litvinenko and the Virginia Tech shooting.

[4] In 2010, Simmons was the first to report that the UK government was paying millions of pounds in compensation to former prisoners of the Guantanamo Bay detention camp.

On 27 August 2012 Simmons left ITN to join NBC News as a London-based foreign correspondent.

In December 2018, Simmons was named Senior International Correspondent for The Today Show on NBC News.