For over 20 years, Neil Lennon has been a familiar face on and off the pitch at Parkhead.

On 24 February, the Celtic manager resigned from his position, with his side 18 points adrift of Rangers and hopes of a tenth league title in-a-row a distant one.

This season has been awash with speculation about if and when he would depart from Celtic, given the club’s failure to secure a win in 11 of their 30 league games, and criticism over a winter trip to Dubai. Until now, he maintained that he would stay.

Neil Lennon, manager of Celtic celebrates pictured winning the Scottish Cup at the final in 2019 (Picture: Getty Images)

Here, we look back at his career highlights as a midfielder, and two-time manager of the Hoops team.

When did Neil Lennon join Celtic?

Lennon first appeared on the pitch at Parkhead in December 2000 after signing for £5.75 million under his former manager at Leicester City, Martin O’Neill.

The midfielder supported the Glasgow club from his time as a young boy in Lurgan, County Armagh, and has said in his resignation statement: “I will always be a Celtic supporter myself and I will always want the best for Celtic."

He was a holding midfielder in his seven years at Celtic, focusing largely on defence and only managing three goals from 2000 until he left the team in June 2007, moving to Nottingham Forest.

He returned as caretaker of the club in March 2010, and one month later he was signed as the manager and remained at the club until 2014.

Lennon then returned as interim-manager, to fill the boots of Brendan Rodgers who left Celtic mid-season in February 2019, and Lennon secured his second stint as manager in May that year.

Following success at securing the quadruple-treble, Celtic fans were content with the 49-year-old’s results, but the relationship between fans and manager has soured with bitter rivals easing towards their first title since 2011.

What are some of his career highlights?

Lennon has said that the highlight of his nearly three decades in professional football was clinching the quadruple treble in December 2020 - 20 years after his career at his beloved club began.

Winning the quadruple in 2020 against Hearts at Hampden, he said: “It's very special for me from a personal point of view.

“For me, this is the best accomplishment of my career, achieving this as a manager. I wanted the treble, I didn’t do it the first time, and now I join an elite band of managers here at the club, and I couldn’t be happier with that.”

Lennon also enjoyed great success during his time as a player, including being appointed captain when Gordon Strachan took over from O’Neill in 2005.

In Lennon’s first season, he earned three winner's medals as Celtic swept to a domestic treble, winning the Scottish Premier League, Scottish Cup and Scottish League Cup.

The following four seasons saw Lennon win a further two league championships and two Scottish Cups. He was also an integral part of the Celtic side that reached the UEFA Cup Final in Seville in 2003, losing 3-2 to Porto after extra time.

The Northern Irishman made 304 appearances for the club in his playing career which included five Scottish Premier League titles, four Scottish Cups, two League Cups and the UEFA cup final.

When he returned in 2010, he enjoyed a quick round of success with the team he had been handed from Tony Mowbray.

However, the loss against Ross County in the 2010 semi-final of the Scottish Cup saw him describe the team as “lacking hunger and desire”, before a mass exodus of players made way for Lennon’s newly signed team.

This included some of his best players in his first stint as a Celtic manager, such as Izaguirre, Hooper, Ledley and Kayal.

His first two seasons were not smooth, but the club went on to win the 2011–12 Scottish Premier League. The highlight of the season came in the form of an unlikely 2-1 win over Pep Guardiola’s Barcelona in the Champions League.

In April 2013, Celtic retained the Premier League title and Scottish Cup.

In the 2013-2014 season, the team had a disappointing run at the Champions League but fared better in the Scottish League, scoring 102 goals on the way to their third successive League title.

Lennon left the club that June, with controversy over his reason why - having received death threats and bomb scares during his run as Celtic manager.

However, he returned in 2019 to support Scott Brown and the team on their way to a treble-treble victory as interim manager, before signing a 12 month contract as manager.

The success didn’t stop there and in December 2020, the boys in green secured the Scottish Cup with a tense penalty shootout triumph, sealing the historic quadruple treble.

Why did he resign?

This season has been anything but exciting for Celtic, despite the 2020-2021 season beginning with the prospects of a fifth consecutive treble.

Following the 2-0 Old Firm home loss to Rangers on October 17, Lennon’s team failed to get past the Champions League group stage, before insult was added to injury when they were eliminated from the Europa League and from the League Cup in the second round.

Their unstoppable run of 35 domestic cup wins was halted by Ross County, who prevailed 2-0 at Celtic Park in the League Cup last 16.

Fans protested and clashed with police outside the stadium in December 2020, with Lennon telling reporters: “On the [protests], we're hurt and disappointed.”

Lennon added: "I understand the frustrations of the supporters because we are not in a great run at the minute. But it serves no purpose, particularly for the players.

"I'm old enough and big enough to take criticism and abuse. Some of it is justified and some of it is over the top. That is the role of a manager and that is the responsibility you have to bear.”

In January 2021, the squad ventured on their annual Dubai training trip in the height of a pandemic and resulted in the isolation of 13 players – plus Lennon – for a draw with Hibernian.

It has now been reported that Celtic bosses called meetings at the beginning of this week (22 February), following a poor run of results culminating in Sunday's 1-0 loss to County, who were bottom of the table heading into the fixture.

In his resignation statement on Tuesday 23 February, Lennon said: "We have experienced a difficult season due to so many factors and, of course, it is very frustrating and disappointing that we have not been able to hit the same heights as we did previously.

"I have worked as hard as ever to try and turn things around, but unfortunately we have not managed to get the kind of run going that we have needed.

"I have always given my best to the club and have been proud to deliver silverware to the Celtic supporters. The club will always be part of me. I will always be a Celtic supporter myself and I will always want the best for Celtic."

What have other Celtic players and colleagues said about him?

Celtic chief executive Peter Lawwell has paid tribute to the ‘Celtic man’, following his departure from the club.

He said: "[Lennon] served the club with distinction as both player and manager.

"Neil has always been and will always be a true Celtic man and someone I will always hold in the highest regard.

“Personally, it is a sad day for me to see Neil leave. Neil is a man of quality and decency, he is someone who will always be part of the fabric of Celtic and someone who will always be welcomed."

Meanwhile, former Ranger manager Ally McCoist said he wasn’t surprised at his resignation, and that he needed to have some normality back in his life.

He told TALKsport: “in terms of the decision itself, I’m not overly surprised at all. I think the way the season has gone for Celtic this year has effectively been one disaster after another, and there are a lot of people responsible for that.”

The Rangers legend added: “hopefully he can get some sanity back in his life and go and enjoy himself and relax with his family for a period.

“That’s the one thing, looking at Neil, that he needs and wants – so that’s the most important thing.

“He needs to spend some time away from the pressure that is being an Old Firm manager.”

Others who paid tribute included former Celtic player Chris Sutton, who tweeted: “Neil Lennon had to go.

“I know this season has been a disaster but I hope after the anger settles down about this season that people respect that Neil has been a great servant to Celtic both as a player and manager.”

Celtic’s Principal shareholder Dermot Desmond described Lennon as a "Celtic legend".

"He has given so much to the club, and with his success over the last number of years - including winning a treble in his own right - he will be very difficult to replace," he said.

Why did Neil Lennon leave Celtic? Hoops manager resignation explained - and his football career timeline