[17][18][19] In 1910, after a dispute among a number of board members, Kalafatis with most of the players—also followed by Campbell—decided to pull out of POA and secured a new ground in Amerikis Square and the next year the team won the 1911 SEGAS Championship.

In 1918, the team adopted the trifolium (shamrock) as its emblem, symbol of harmony, unity, nature, fertility and good luck,[20][21] as proposed by Michalis Papazoglou.

[9][27] Notable players included the captain Mimis Domazos, Anthimos Kapsis, Aristidis Kamaras, Kostas Eleftherakis, Totis Filakouris and the goalkeepers Takis Ikonomopoulos and Vasilis Konstantinou.

In the same year, Panathinaikos played for the 1971 Intercontinental Cup (due to the refusal of Ajax to participate), where they lost to Uruguayan club Nacional (1–1 in Greece, 2–1 in Uruguay).

Saravakos, a high-technique explosive midfielder and iconic captain of Panathinaikos, was the alsolute idol for the fans during the 1980s, while other players included Nikos Sarganis, Spiros Livathinos, Velimir Zajec, Juan Ramón Rocha, Christos Dimopoulos and Giannis Kyrastas.

In the 1984–85 season, Panathinaikos, with coach Jacek Gmoch and stars Dimitris Saravakos, Velimir Zajec, Juan Ramón Rocha and Ioannis Kyrastas, made a run in Europe, eliminating Feyenoord, Linfield and IFK Göteborg to reach the semi-finals of the European Cup, where they were knocked out by Liverpool.

[30] In 1995–96, with Juan Ramon Rocha as coach and key players Krzysztof Warzycha, Józef Wandzik, Stratos Apostolakis, Georgios Georgiadis, Dimitris Markos, Giannis Kalitzakis, Giorgos Donis and Juan Jose Borrelli, Panathinaikos reached the Champions League semi-finals, finishing first in the group stage against Nantes, Porto, Aalborg BK and eliminating Legia Warsaw in the quarter-finals.

En route, the Greek team had knocked-out Litex Lovech, Fenerbahçe (with an impressive 4–1 win in Leoforos Alexandras Stadium), Slovan Liberec and Anderlecht.

During the quarter-finals, although winning the first match in Estádio das Antas against eventual winners of the trophy FC Porto of José Mourinho, with the header of Emmanuel Olisadebe, they were eliminated in the second leg after extra time.

On 22 April 2008, and under pressure from the fan base, main shareholder Giannis Vardinogiannis gave a press conference in which he announced the decision of his family to reduce their share in the club to 50%—after 30 years of full ownership—through an €80 million increase of the company's capital stock.

Following the major changes in 2008, Panathinaikos hired Henk ten Cate as coach and bought many expensive players, such as Gilberto Silva from Arsenal and Gabriel from Fluminense.

During the summer transfer period, the club bought Djibril Cissé from Marseille, Kostas Katsouranis from Benfica, Sebastián Leto from Liverpool and various other players, spending more than €35 million in total.

The team managed to reach the last 16 of the Europa League, eliminating A.S. Roma after two amazing matches in Olympic Stadium of Athens and Stadio Olimpico.

[37] In 2011, due to financial problems and management disagreements, Panathinaikos sold Cissé for €5.8 million to Lazio and first-choice goalkeeper Alexandros Tzorvas to Palermo to reduce the budget.

[40] However, the owner of Skai TV, Giannis Alafouzos, devised a plan to take Vardinogiannis' shares (54.7%) and make them available to fans around Greece so that everyone could contribute a desired amount, so that Panathinaikos could overcome the crisis.

After a few weeks of operation, 8,606 members had signed up, some of which were current or former Panathinaikos players, including Jean-Alain Boumsong, Sotiris Ninis, Gilberto Silva and Djibril Cissé, among others.

Starting the football year, both fans and journalists were very sceptical of Panathinaikos' chances of a successful season, and many people expected the team to suffer relegation from the Super League Greece.

Despite the early scepticism, Panathinaikos' fans supported the team through the rough start, and the season turned out to be a massive success in light of the dire financial situation of the club and the young and inexperienced squad.

The club finished fourth in the regular season and second after the playoffs (meaning they qualified for the 2014–15 Champions League), with Marcus Berg the top scorer of the team.

Further successive poor results under the latter's reign, combined with loss of dressing room control, led to the dismissal of Stramaccioni on 1 December 2016, with former Panathinaikos player and Greece international Marinos Ouzounidis taking over the management at the club.

[46] Coach Donis had a great start of the season despite beginning with −6 points in the championship, counting 6 consecutive wins that put Panathinaikos on top of the table.

[51] During the 21-22 season under the management of Ivan Jovanović, the team achieved its major goal of returning to European Competitions finishing fourth, and won their 19th Greek Cup, beating PAOK 1–0 in the final ending an eight-year trophy drought.

After a five-year absence from European Competitions, Panathinaikos has won a place in the third qualifying round of the 2022–23 UEFA Europa Conference League, drawing Czech Slavia Prague.

[57] He was possibly inspired by Billy Sherring, an Irish Canadian athlete who had won the Athens 1906 Olympic marathon (1906 Intercalated Games) wearing a white outfit with a big green shamrock on the chest.

Capacity was reduced from 25,000 to 16,620, new dressing rooms were built and modular stand roofing was added in compliance with UEFA requirements, but in 2004, stricter standards were announced and the Leoforos Alexandras Stadium would need further expansion were it to remain suitable for UEFA-sanctioned matches.

As of October 2013, and due to the club's and the country's financial troubles, the construction of the Votanikos Arena has stopped and consequently the plans for the demolition of the Leoforos Alexandras Stadium have been put on hold.

The current president of the club, Giannis Alafouzos, declared his intention for another renovation of the stadium and the capacity increase, while the Panathinaikos Movement made its propositions for a total reconstruction.

In 2012, the owner of Skai TV, Giannis Alafouzos, devised a plan to take Vardinogiannis' shares (54.7%) and make them available to fans around Greece so that everyone could contribute, so that Panathinaikos could overcome the crisis.

Current sponsorships: Panathinaikos was founded by middle class athletes (with Giorgos Kalafatis as a key figure) aiming of spreading and making more known football to the Athenian and Greek public in general.

Moreover, they have been sharing since the early 10s' close relations with Dinamo Zagreb's Bad Blue Boys[70] (based on their common rivalry with Red Star and Olympiacos fans, capital city teams and mutual respect for each other's ultras achievements) and also with Fedayin of A.S. Roma based on the capital city team factor, their mutual respect and the ancient Athens and ancient Roma cultural connection.