Mark was appointed to the Board of Frantic Assembly as Chair in early 2020.

Mark has a substantial track record as a trustee in the theatre. He is the longstanding deputy chair of the board of trustees and performs (unpaid) the lead executive role on behalf of The Royal Theatrical Support Trust (RTST) — a grant-giving and facilitating charity dedicated to supporting the theatre, especially regional theatre, and early-career theatre practitioners. In 2016, Mark originated the RTST Sir Peter Hall Director Award scheme involving an annual competition among early-career directors, which he continues to organise and manage each year in collaboration with a different regional mid-scale producing theatre company and its co-producing theatre partners, together with a different panel of judges each year, typically comprising some of the leading names in British theatre. Each roll-out of the scheme catalyses a career-transforming, first-time opportunity for the winning director to originate and direct a fully-funded production on the mid-scale at the participating regional theatre —supported by a production grant from the RTST— and then to take it on a national, mid-scale tour. The scheme has been successful in propelling the careers of individuals who experience racism (including two out of four winners thus far) and women (including three winners), and in bringing about productions that might otherwise never have been funded because of the risks of backing an early-career director. The scheme has earned prestige in the industry. It was the joint largest beneficiary of the proceeds of ATG's West End run of Sir Ian McKellen's solo show marking his 80th birthday.

Mark graduated in Law from King’s College London in 1983, and pursued a career as a City of London solicitor, from which he recently retired in order to pursue his interests in the theatre. He practised for six years as a corporate finance and investment banking specialist with international law firm, Freshfields before joining London law firm, Bristows LLP, where he was a Partner for some 25 years until 2020. He was head of Bristows' Life Sciences and Technology-focused Corporate practice for some 14 years, and head of its Charities & Not-for-Profit practice for the last 10 years. He was recommended multiple times, both as a corporate lawyer and as a charity lawyer, by the annual independent legal directory Legal 500. Matters on which he has advised include: some of the earliest UK university biopharmaceutical corporate spin-outs; AstraZeneca's first-ever corporate spin-out; an international media joint venture that created the world’s first digital interactive satellite TV platform, ultimately rolled into Sky Digital; and major governance reforms of some of the UK’s leading professional and charitable institutions established by Royal Charter, and of a United Nations-backed international non-profit organisation; and a myriad of governance and other matters for medical research, mental health, animal welfare, arts and heritage charities. He is a continuing member of the Charity Law Association and of the Association of Chairs.

Mark was long-term head of Bristows' graduate recruitment programme and senior member of the firm's Inclusion Committee, and he co-founded Bristows' LGBT+ network.

In 2020, Mark made the most of lockdown by successfully undertaking a unit of a degree course in Theatre Studies at Yale University.