From July 2015 to February 2016 he served as a campaign director for the Liberal Democrats. Since March 2016, he works as head of government relations for Huawei Technologies, a global ICT solutions provider.  As a former special adviser, he did not need to seek the approval of the advisory committee on business appointments (ACOBA) to take on the role.
Lumsden was a political consultant for the Greater London Authority for two years between 2012 and 2014. Before this, he was leader of the London Borough of Lambeth Liberal Democrat Group for seven years. 
Lumsden was a London Agent for the Liberal Democrats between 1999 and 2012. In May 2002 he took up the role of executive member for finance at the London Borough of Lambeth for four years. He was also the chair of the pension fund for the London Borough of Lambeth. 
- HM Government July 2014, Dods Monitoring, accessed 22 September 2014
- Omar Oakes Streatham councillor Alex Davies elected new Lambeth Lib Dem leader Streatham Guardian, 6 March 2014, accessed 16 October 2014
- Linkedin | Ashley Lumsden, Linkedin, accessed 10 November 2016.
- Ashley Lumsden LinkedIn profile, accessed 22 September 2014.