It forms part of a wider club loan with several other banks, totalling £190m.
The transaction will enable the all-day café-bar operator to continue its plan to roll out over 30 new sites a year.
OakNorth debt finance director Stuart Blair said: “Loungers is a best-in-class operator with a differentiated and highly scalable model.
“The business has shown impressive resilience through multiple macroeconomic cycles and continues to deliver outstanding site-level economics.
Next stage
“It’s been a pleasure to work alongside Fortress and Lion Capital – two highly experienced sponsors with a deep understanding of the hospitality sector – to support the next stage of Loungers’ growth journey.”
The £354.4m acquisition from Fortress Investment Group, which also owns Punch Pubs, was originally voted through at the end of January.
Founded in 2002 and headquartered in Bristol, Loungers operates some 290 sites across the UK under the Lounge, Cosy Club, and Brightside brands and employs more than 9,000 team members.
In March, Loungers opened its “milestone” 250th site, the Rivolo Lounge in Norwich.
Loungers CEO Nick Collins as well as chairman and co-founder Alex Reilley will retain their positions within the business and remain “a driving force” under Fortress and Lion’s ownership.
Challenges and opportunities
On the acquisition, Reilley said: “We’re hugely excited about what the future holds for Loungers.
“Having the backing of both Fortress and Lion Capital provides us with the firepower and strategic support to continue our ambitious expansion plans while staying true to the culture and values that have made Loungers so special.
“Throughout this transaction, OakNorth has been an outstanding banking partner - responsive, commercial, and supportive at every step.
“They are long-term supporters of the hospitality sector and have a deep market understanding of the challenges and opportunities facing businesses like ours.”