Which manager led Manchester United to the Treble in 1999?

Alex Ferguson led Manchester United to the Treble in 1999.

United's Treble comprised the Premier League, FA Cup, and UEFA Champions League, all won during the 1998–99 season. It was the first time an English club had completed that combination, making the achievement the defining triumph of Ferguson's Manchester United career.

The campaign was built on resilience. United overcame Arsenal in an FA Cup semi-final replay and Juventus in the Champions League semi-finals before facing Bayern Munich in the final in Barcelona. Bayern led for most of the match, but Teddy Sheringham equalized in stoppage time and Ole Gunnar Solskjær scored the winner moments later.

Ferguson had managed United since 1986 and had already ended the club's long wait for a league title in 1993. The 1999 success brought him a knighthood later that year. A frequent mix-up is treating the League Cup as part of the Treble; United reached its quarter-finals, but the third major trophy was the Champions League, not the League Cup.