Jackett died on Thursday, with his passing confirmed by multiple clubs and the League Managers Association on Friday. He was born in Watford on January 5, 1962, and spent his entire ten-year professional playing career at Watford, making 428 appearances and winning 31 caps for Wales as a left-footed defender or midfielder.
His managerial career began at Watford during the 1996-97 season, following a spell as assistant coach to Ian Holloway at Queens Park Rangers. He went on to manage Swansea City, Millwall, Wolves, Rotherham United, Portsmouth and Leyton Orient across nearly 30 years in the dugout, taking charge of more than 900 games in total.
He won promotion at three different clubs. At Swansea, appointed in 2004, he led the club to League Two promotion in his first season and won the EFL Trophy and the FAW Premier Cup. At Millwall, where he managed for six years from 2007, he won the League One play-off final in 2010 and reached an FA Cup semi-final against Wigan Athletic in his final season before resigning in 2013.
He joined Wolves later that year with the club in League One following back-to-back relegations. He delivered an immediate promotion, winning the League One title with a record 103 points — still the division's all-time record. Wolves came close to a play-off place the following season before he was dismissed after the club's takeover by Fosun International.
He subsequently managed Rotherham United, where his side narrowly avoided relegation, before taking charge at Portsmouth from 2017 to 2021. At Fratton Park, he reached the League One play-offs in both 2019 and 2020, winning the EFL Trophy in the first of those seasons and finishing runner-up in the second.
His final managerial role was at Leyton Orient. He later returned to football as director of football at Gillingham in January 2023, before stepping down in November 2024 for medical reasons.
Millwall's tribute described him as "one of the Lions' greatest-ever managers" and "a man who gave Lions fans moments to remember for life," adding: "Kenny managed over 300 games during his time with the club, leading The Lions to promotion from League One and to an FA Cup Semi-Final. Rest in peace, Kenny."
Wolves said: "Kenny led the club to its incredible record-breaking League One title and laid the foundations for the club as we know it today. The thoughts of everyone at Wolves are with Kenny's family and friends at this time."
LMA chief executive Richard Bevan offered perhaps the most complete summary of a career built on substance over noise.
"Kenny stands as one of the most respected managers to have plied their trade in the EFL, a hugely capable leader whose work across four decades has left a lasting influence on the many players, coaches and colleagues who benefitted from his guidance. He embodied everything we like to see in a manager: humility, professionalism and a deep care for his players and staff. He improved every club he served and did so with quiet dignity throughout his career."
Across Watford, Swansea, Millwall, Wolves, Rotherham, Portsmouth and Leyton Orient, that quiet dignity left a mark that outlasted every dugout he occupied.