Matt Davies, who is leaving Tesco after its £3.7bn takeover of wholesaler Booker completes, will succeed Andy Higginson in the role with effect from 1 May.
The announcement comes a day after the story was first reported by Sky News.
Mr Higginson said: "Matt is a first-class retailer and brings a wealth of experience to the group."
N Brown, which trades under brands such as JD Williams, a department store concept, menswear label Jacamo and Simply Be, a fashion range aimed at larger women, has been searching for Mr Higginson's replacement for months.
He joined Tesco in 2015, when it was recovering from the accounting scandal which saw Britain's biggest retailer pay more than £125m to settle a case brought by the Serious Fraud Office.
Tesco announced just weeks ago that Mr Davies would step down after the Booker deal closes, with Charles Wilson, the wholesaler's boss, replacing him as head of the broader UK and Ireland (Other OTC: IRLD - news) operations.
Headquartered in Manchester, N Brown - led since 2013 by chief executive Angela Spindler - employs more than 2,600 people in the UK and has a market value of just over £535m.
Mr Davies said: "I am delighted and excited to be taking on this role.
"I am really looking forward to working with Angela, her team and my fellow Non-Executive Directors to further develop and grow the N Brown business."