He joins Saracen Fund Managers, the Edinburgh-based independent, as investment director working alongside the teams managing Saracen's two funds.
Mr McKenzie said that after several years of hard work, the Piecebox business he created with his wife was "beginning to look fairly promising", and he had decided to look for an opportunity to return to the industry. "It was my intention to do something different, and thinking about coming back is something that has happened fairly recently."
Saracen recently lost the co-manager of its Global Income & Growth Fund in tragic circumstances when Citywire-rated Daniel Leaf, 55, died in a hillwalking accident. Managing director Graham Campbell said Mr McKenzie had not been recruited in response to that but was part of Saracen's ongoing strengthening.
Mr Campbell said Mr McKenzie had almost 20 years' experience and had been a Citywire-rated manager at both Aviva and Martin Currie. He said: "Scott is a talented analyst and his wealth of experience will add an interesting dynamic to our team and support the growth of Saracen Growth and Saracen Global Income & Growth funds."
The Piecebox cafe opened in Edinburgh in January 2011 and also runs a successful outside catering business serving a wide range of customers across the city.
Mr McKenzie joined Martin Currie in October 2005 from Aviva where he had managed a £228 million equity income fund for Morley Investment Management. He left Currie in September 2009 "to pursue other opportunities" which he said would be outside the industry.
His £21m UK equity income fund had endured a difficult period, losing 30 per cent over three years against a loss of 18 per cent for the all-share index, according to reports at the time.
It is now part of Currie's £112m global equity income fund, which ranks 12th out of 19 sector funds over the past three years, according to Money Management.
Mr McKenzie said: "I am looking forward to returning to the fund management industry and working with Saracen to help them achieve significant growth."