[2] The club enjoyed their greatest successes during the 1960s and 1970s under Jock Stein when they won nine consecutive league titles and the European Cup.
[3][4] He managed Celtic to nine consecutive league titles and led them to their European Cup Final triumph over Inter Milan in 1967.
[5][6] His role was quite different to the modern style of manager or head coach; he never worked with his players in training and only watched games from the director's box.
[10] The next decade saw Maley lead Celtic to a further four successive league titles between 1914 and 1917,[1] during which time they went on an unbeaten run for 62 games from 13 November 1915 until 21 April 1917.
[11][12] This remained a British record for an unbeaten run in professional football until it was surpassed by Brendan Rodgers' Celtic over 100 years later.
[9] He remained in his post for almost 43 years, the longest serving manager in the club's history, and guided the team to 30 major trophies.
[15] His time as manager, however, is considered largely a period of underachievement, and with chairman Robert Kelly's domineering influence in the running of the club, many questioned how much say McGrory had in team selection.
[5][14][16] Jock Stein left Hibernian to become manager of Celtic in 1965, with McGrory taking on the role of the club's Public Relations Officer.
[24][25] In his second full season as manager, Stein led Celtic to success in all five competitions they took part in (a "quintuple"),[3] most memorably their 2–1 win in Lisbon over Inter Milan in the 1967 European Cup Final.
[27] He was seriously injured in a car accident in July 1975 and spent the next year recuperating, with assistant manager Sean Fallon taking over managerial duties for the season.
[36] Hay was unable to cope with high spending Rangers the following year, and on failing to win any trophies was sacked by the club.
[5] After losing to Falkirk in the semi-final of the Scottish Cup, Burns was sacked and his assistant Billy Stark took charge for the few remaining games of the season.
[1] Despite losing his first two games of the season,[47] Jansen quickly turned things round and won the club's first Scottish League Cup in 15 years when they beat Dundee United 3–0 in the final.
A poor start to the season put Vengloš under pressure, but the arrival of new signings and a 5–1 win over Rangers in the league gave rise to optimism.
However the league deficit was too much to claw back and a Scottish Cup final defeat to Rangers sealed a largely disappointing season.
[5] A shock Cup defeat at home to Inverness Caledonian Thistle saw Barnes sacked and Dalglish taking over as caretaker manager for the rest of the season.
He also guided Celtic to their first UEFA Champions League knockout stage in 2006–07[59] and repeated the feat in 2007–08[60] before departing the club in May 2009, after failing to win the SPL title.
[63] Celtic narrowly lost out to Rangers in the league in Lennon's first season in charge, but he did gain consolation by defeating Motherwell 3–0 in the 2011 Scottish Cup Final.
[73][74] In November 2017, Celtic defeated Motherwell in the 2017 Scottish League Cup Final,[75] before a seventh consecutive league title was clinched in April 2018,[76] with Celtic then going on to defeat Motherwell in the 2018 Scottish Cup Final to clinch a second consecutive domestic treble (the "double treble"), the first club in Scotland to do so.
[81] Into the first full season of his second spell as manager, Neil Lennon led Celtic to a 1–0 win over Rangers in the 2019 Scottish League Cup Final, the club's tenth consecutive domestic trophy.
[85] The completion of the 2019-20 Scottish Cup was delayed due to the ongoing COVID-19 pandemic, with the semi-finals and final not taking place until late autumn/ winter of 2020.
The match went to penalty-kicks after the sides tied at 3–3 after extra time, with Celtic going on to win the penalty shoot-out to clinch a fourth successive treble.
[90] Improved form in October saw Postecoglou win the Manager of the Month award,[92] with new signings Jota and Kyogo Furuhashi flourishing in the side.
[94] Celtic made a strong start to the following season, and by New Year (2023) were nine points clear of second-placed Rangers in the league, with a significantly higher goal difference.