SushiDog has secured £800,000 in funding from investor Middleton Enterprises to open four new sites in London.
It comes after Middleton Enterprises, whose portfolio includes gym chain OneGym and landlord platform One Utility Bill, provided £612,000 to the quick-service sushi business in April last year.
SushiDog launched as a kiosk at the Westfield London shopping centre in 2018 and serves sushi rolls, bowls and salads made fresh-to-order in front of customers.
It has since expanded to six London locations, with sites opening in Baker Street and on the Strand last year following its first round of investment.
The business has committed to a growth target of opening 30 SushiDog restaurants over the next five years.
Greg Ilsen, co-founder of SushiDog, said the business had seen a 77% increase in revenue year-on-year off the back of an "astonishing" performance across its London sites.
He said the investment would allow the restaurant group to expand at a rate "that matches our ambitions".
James Middleton, senior investment associate at Middleton Enterprises, said: “We back businesses that we know have the potential to succeed and SushiDog continues to deliver on its potential, even outperforming our initial expectations.
"As a result, we’re absolutely delighted to have reached a second round of growth investment in less than a year. This level and frequency of investment isn’t that common, it’s a testament to the founders and the faith we have placed in them and their business model.”