Mr Howell will replace Mark Duckworth who has decided to step down after 10 years at Openwork, five as chief executive.
Mr Duckworth steered restricted network Openwork, which has 3,900 advisers, through its independence from Zurich Insurance Group in 2018 and helped the company notch up pre-tax profits of £22.6m in 2018.
Openwork said that after 10 years with the company Mr Duckworth decided it was the right time to leave to pursue other opportunities in the market.
New CEO Mr Howell was chief executive of wealth manager Rathbones until May 2019. During his 5-year tenure funds under management grew from £22bn to £47.5bn.
Prior to Rathbones he was chief executive of Williams de Broe Wealth Management and chief executive of Fortis Private Banking. He also worked in international banking for 24 years with Barclays.
Mr Howell, said: “The market demand for financial advice continues to grow unabated. As a long established, now adviser-owned business and ranking among the Top 3 financial services networks in the UK, Openwork is already very well positioned.
“I very much look forward to working with our partners and management team in realising the full potential of the business.”
Outgoing chief executive Mr Duckworth said: “I am incredibly proud of what we have achieved together over the past 10 years for our clients, our business and our culture.
“I feel that it is now the right time to hand the baton over to a successor to drive the next phase of Openwork's strategy and development as an independent, adviser-owned business.
“I would like to thank Openwork’s advisers, staff and the board for all of their support over the past 10 years and wish everyone continued success for the future.”
Openwork group chairman Christopher Rodrigues said: “On behalf of the board and shareholders, I would like to place on record our gratitude to Mark for all he has done to develop the Openwork franchise; during his tenure the Group’s financial performance has been transformed.”