He replaces Lord Chadlington, who is stepping down after seven years.
Lord Chadlington will become a life president of LAPADA, alongside former chairman Earl Howe.
Entrepreneur and army reservist Rupert de Mauley will now attend board meetings, annual general meetings and the selection committee for the LAPADA fair.
LAPADA chief executive Rebecca Davies said: “Lord Chadlington has overseen significant improvements both in our financial strength and in our influence in the trade and the wider world. Lord de Mauley will build on these successes. It is important to have a chairman who is able to make an impact at a high level [in government].”
LAPADA also announced changes among its board of directors.
Consultant and freelance journalist Jacqueline Pruskin has stepped down and will be replaced by digital advertising specialist and art collector Victor Benady. He sits on the Royal Academy Schools fundraising committee and is currently working on projects with Liberty and the V&A.