She was co-convenor of the Scottish Greens from November 2013 to August 2019, serving with Patrick Harvie, and was the party's lead candidate for the 2019 European election.

[4][5] She grew up there, educated at a mixed-race school, with the country having achieved independence from the United Kingdom as the Republic of Zimbabwe whilst she was a baby.

[11][12] Until June 2015 she was a lecturer in cultural geography, environmental ethics and social justice at Edinburgh Napier University.

[16] During her time as a councillor, Chapman has advocated for causes that include: the living wage, participatory budgeting, better private tenancy rights,[17] and better support for non-profits.

[20] In November 2013, she was elected unopposed as the Scottish Greens' female co-convenor, succeeding Glasgow councillor Martha Wardrop,[21] and was re-elected to the position in 2016.

[20][22] Chapman was the party's lead candidate in the 2014 European Parliament election in the United Kingdom for the Scotland constituency.

The election was notable as it was the first time an incumbent co-convenor faced a serious challenge, all to date had been re-elected as the sole nominees.

The MSP said she agreed with children as young as 8 being allowed to make their own decision about whether to legally change their gender.

A document released by the University indicated that the election committee disagreed with the initial decision to annul the results as Chapman had not been given a right of reply to the allegations but did not overturn it.

Chapman won re-election, defeating Aberdeen law student Israr Khan by a margin of 1,248 votes to 891.

[38] On 10 May 2023, Chapman was sanctioned after the standards committee found she had failed to declare a financial interest during an evidence session on the Gender Recognition Reform Bill.