Halla's broadcasting career started in Beijing. After moving to China in 2005, she began freelancing with local publishing company True Run Media. This included writing travel articles for a local guidebook, before joining the company as a section editor for local lifestyle and entertainment magazine That's Beijing. Four years with the company gave Halla an in-depth feel for Beijing, a city she remains fond of to this day.

Halla was approached by CCTV at this time, and began presenting the weather for the channel. She became one of China's best known English language presenters, and during her 6 years with the Chinese Met Office, she covered major events like the Sichuan earthquake, the Japanese earthquake and tsunami and the Beijing Olympics.

She also presented the news with BON. The channel broadcast Chinese news and content to North America. In addition to the main news programme, Halla presented Mediawatch, a show that analysed the Chinese media and social media trends on a national, regional and local level. This unique show gave a deeper insight into wider Chinese society. 

After a period of freelancing around Southeast Asia, Halla returned to Europe and began working with France 24. During her time at the rolling news network, Halla covered some of the world's biggest events - including breaking news of the Iran nuclear deal being signed, the disappearance of MH 370, the death of Fidel Castro, an attempted coup in Turkey, and Halla broke the result of the EU Brexit referendum.

Terrorism dominated the news agenda during her time at the channel, with several terrorist attacks carried out in Europe, and especially France. Halla was an integral part of the team anchoring rolling coverage of the Charlie Hebdo attacks and memorial, the November Bataclan terror attacks and the attacks in Nice. 

Halla was also the presenter of the weekly Middle East Matters programme on France 24, providing an in-depth view of affairs in the Middle East, but also providing insight into the people and societies of this dynamic region.

After the Brexit vote, Halla returned to the UK to present STV News Tonight. The flagship news programme on STV2 was the first to use the integrated news format: bringing Scottish, UK and International news together in one single programme. It has enabled Halla and the team to cover stories like the Grenfell tragedy, Barcelona terror attacks, Los Angeles shooting, and the North Korean nuclear negotiations. 

Halla joined Al Jazeera English in 2019 as a Principal Presenter for the channel, marking a return to international news at a 24 hour global network. As well as presenting the Newshour, and the flagship Inside Story current affairs programme, Halla has also interviewed news makers around the world, including the Director General of the WTO, the French Finance Minister, UK opposition leader Jeremy Corbyn and politicians and political advisors from around the world.

Halla has also worked closely with Scottish charities, and is a member of Women in Journalism Scotland, supporting women in the media and mentoring young journalists.