She represented the Kowloon West geographical constituency, until November 2020 when she resigned along other pro-democrats to protest against the disqualification of four of her colleagues by the government.

[7] After graduating in 1975, she went to Toronto for pre-university qualifications and in 1979 she obtained a Bachelor's degree in journalism with English studies from Carleton University in Ottawa, Canada.

She was later promoted to chief Hong Kong correspondent for AFP, covering in this role the Tiananmen Square massacre, an event which she describes as a "watershed [...] that cemented my journalistic principles and political beliefs".

The following year, she told a journalist that she did not consider the protests a failure, due to the attention they seemed to have drawn by many to the "plight of the Hong Kong people".

[15] During a 2019 Legislative Council meeting, Pro-Beijing lawmaker Junius Ho made a remark directed toward Claudia Mo, stating that she is used to "eating foreign sausage."

Mo, who is married to British journalist Philip Bowring, later told the council that the comment was "blatantly sexist, racist and it amounts to sexual harassment.

[17] On 6 January 2021, Mo was among 53 members of the pro-democratic camp who were arrested under the national security law, specifically its provision regarding alleged subversion.

[20] She was denied bail in mid-April, with a judgement releasing in late May considering the argument of the prosecution that her exchanges on WhatsApp with Western media were a "threat to national security".