The 20-year-old winger signed a four-and-a-half-year contract at the Stadium of Light, moving to Wearside from Belgian Pro League side Standard Liège.
London-born, Mundle’s career started with his boyhood Club Tottenham Hotspur and he spent 15 years in N17 before departing for Belgium in July 2023.
His final season in North London was a progressive one, as he scored seven goals and assisted five more in 24 Premier League 2 appearances for Spurs’ development outfit.
The 20-year-old’s performances didn’t go unnoticed at Hotspur Way and they were rewarded by former Head Coach Antonio Conte, who promoted him to the first-team squad in early March.
He was subsequently named on the bench five times in the Premier League, following on from his maiden appearance in the North Londoners’ senior matchday squad for an Emirates FA Cup tie last January.