After graduation, she entered a fast track management scheme in 1989 at HSBC which involved working in Australia, Japan and China.

[8][9] Maclean contested the Birmingham Northfield seat in the general election of 2015, finishing second behind the incumbent Labour Party MP Richard Burden, who won a majority of 2,509 votes.

[8] In April 2017, Karen Lumley, Conservative MP for Redditch, announced that she would not contest her seat in the June snap general election due to ill health.

[8] In July, in her maiden parliamentary speech, she commented that her main priority would be 'to fight to protect and strengthen local health services', especially the Alexandra Hospital in Redditch.

In September 2021, following the withdrawal of foreign defence forces from Afghanistan and takeover by the Taliban, Maclean was appointed Parliamentary Under Secretary of State (Minister for Safeguarding) at the Home Office.

In May 2022, during an interview on Sky News, Maclean suggested some people struggling with rising prices could consider working more hours or getting a better-paid job.

[24][25] On 6 July 2022, Maclean resigned from her position as Parliamentary Under-Secretary of State for Safeguarding in protest at Prime Minister Boris Johnson's leadership.

[26] Maclean backed Sajid Javid, then Kemi Badenoch, and finally Liz Truss in the July–September 2022 Conservative Party leadership election.

[30] In December 2023, she was accused by political opponents of transphobia after sharing a social media post about Melissa Poulton, the Green Party candidate for the Bromsgrove constituency.