The intention is that she will succeed Les Platts as chair at AJ Bell's next Annual General Meeting, expected to take place in January 2022.
In the meantime Baroness Morrissey will become a non-executive director at AJ Bell, subject to regulatory and shareholder approval, joining the board as chair designate on 1 July.
She is currently lead non-executive director for the Foreign, Commonwealth and Development Office, reporting to the Foreign Secretary.
Previously she has held a number of financial positions including head of Personal Investing at Legal & General Investment Management and chief executive at Newton Investment Management.
She is also the founder of the 30% Club, a global campaign to increase gender diversity at companies, and has played a leading role in improving the diversity on the board of UK corporations.
Baroness Morrissey said in the announcement that she has “long admired” AJ Bell and “its commitment to helping people invest.”
AJ Bell has also appointed Evelyn Bourke as a non-executive director and she will also join the board on 1 July.
Ms Bourke is currently a non-executive director at Marks & Spencer Group and a non-executive director and chair of the audit committee at Bank of Ireland Group. Until December 2020 she was chief executive of Bupa and has previously held senior roles at a number of financial services businesses including Friends Provident, Standard Life and Chase de Vere.