Dean Proctor will take up the role with effect from 8 April, subject to regulatory approval.
Mr Sheridan held the position for 17 years and the firm says he “has decided that now is the right time to retire from his position.”
7IM says Mr Sheridan will be available “to ensure a smooth CEO transition and will continue to be involved with 7IM in an advisory capacity”.
Under his leadership, 7IM has grown from a start-up discretionary fund manager in 2002 to a business with £14bn of assets under management, providing investment management, service and technology, primarily to Financial Planners.
Mr Proctor has more than 25 years’ experience in financial services, most recently as a managing director at Barclays, heading the unsecured lending business in the UK.
Prior to this, he was the executive general manager for the Commercial Bank of Qatar, based in Doha, and the CEO of Arbuthnot Latham, based in London.
Mr Sheridan said: “7IM has been a great experience and I am proud to be leaving the business at this time with a great range of clients and the strongest management team it has ever had.
“Over the years it has been my pleasure and privilege to work with many of the leading UK advisory firms.
“I have seen many of these firms go from strength to strength and hope that 7IM will be able to continue supporting their growth.”
Mr Proctor said: “I am excited to be joining 7IM at this stage of its evolution.
“The business truly has a track record of innovation from being early into multi-manager and platforms, the launch of its ground breaking AAP fund range in 2008, its award winning app 7IMagine, and most recently the launch of the 7IM Retirement Income Service.
“One of my key focusses will be building on this legacy of innovation as well as getting to know our advisory partners.”
Justin Urquhart Stewart, co-founder and corporate development director said: “I warmly welcome Dean to 7IM.
“He brings significant UK financial services leadership experience with a strong knowledge of wealth management and I look forward to working with him and the management team to build on the great reputation of 7IM.”