In the 1960s, the school was associated with UNESCO, and expanded French language teaching began, since 1991 conducted by the bilingual section.

Since the beginning of the Polish institution's existence, the scout troop Błękitna Czternastka [pl] has been operating alongside it, and since 1989, the Alumni Association of the Karol Marcinkowski Gymnasium and High School has also been functioning as an auxiliary organization.

Over the years, the school has published numerous magazines and is also the organizer of a nationwide theater festival and local TED conferences.

In 1899, Johann Frydrychowicz, the last chairman of the Jeżyce council, who lacked the support of his colleagues, leased a plot of land located at the intersection of Bukerstrasse (now Bukowska) and Cesarzowa Wiktoria (now Grunwaldzka [pl]) streets.

[1] After the annexation of Jeżyce to Poznań in 1900, the Prussian authorities decided to build a German state gymnasium at this location, intending to increase the number of secondary schools in the city (at the end of the 19th century, there were eight, including three boys' gymnasiums: the Catholic St. Mary Magdalene, the Evangelical Friedrich Wilhelm, and the Real Gotthilf Berger).

[8] On 1 April 1919, the Commissariat of the Supreme People's Council appointed Antoni Borzucki [pl] as the first director of the State Gymnasium named after Karol Marcinkowski.

After their subsequent moves to a tenement house on Wyspiańskiego Street in September 1921, the Ignacy Paderewski Gymnasium [pl] was established there as an independent institution.

[11] On 7 December 1923, the Association of Friends of the Gymnasium named after Karol Marcinkowski was founded, bringing together alumni and their families to provide financial support to students and equip classrooms.

In 1921, a medical office (run by Jan Adamski for a long time) was established, and eight years later, a dental clinic.

As a result of wartime activities and repression by the occupiers, 14 pre-war teachers and 119 students (including 10 graduates of the German gymnasium) perished.

[5][7] The functioning of the institution under the pre-war organizational system as the Gymnasium and High School named after Karol Marcinkowski was resumed on 15 February 1945, still during the battle for the city.

At that time, the pre-war Polish language teacher (working at Marcinek and the Gymnasium of St. Mary Magdalene) Czesław Latawiec [pl] was appointed as the first principal.

[12][13] Information about the resumption of classes was posted on handwritten cards distributed in the city by participants of secret gatherings during the war.

[7][8] Even before moving to Różana Street, students organized a march under the windows of the then seat of the Curatorium with a banner reading Wandering Gymnasium and High School No.

On 30 October 1945, the Błękitna Czternastka Scout Troop was reactivated, and on 7 November 1946, on the hundredth anniversary of Karol Marcinkowski's death, a new school banner was funded.

In 2001, the Karol Marcinkowski Bilingual Gymnasium with French language began its activity, taking over the function of the "0" class.

[4][3] In connection with the education reform of 2017, it was decided to return to the system from before 2001, i.e., a four-year high school preceded by a French-language introductory class.

[12] Due to the school's association with UNESCO, a solemn ceremony took place in the auditorium on 28 October 1970 to commemorate the 25th anniversary of the United Nations.

Since 1995, the association has also been organizing annual meetings on the second Saturday of May to commemorate the full five-year anniversaries of graduated in exams.

[18] The school complex occupies a plot of land measuring 1,200 m2 in the triangle formed by Bukowska, Grunwaldzka, and Szylinga streets, adjacent to the Poznań Old Zoo.

The hall on the ground floor, covered with neo-Gothic lierne vault, is flanked by two spacious staircases leading to the auditorium.

In the northeast corner of the plot, a separate building housing the gymnasium was located, with a botanical garden attached to it from the south.

[5][6][7] The central, elevated part of the second floor, crowned with a tower with a clock and a platform for astronomical observations, houses the auditorium with an area of 326 m2, covered by an ornate wooden hanging ceiling.

Karola Marcinkowskiego (Karol Marcinkowski Gymnasium and High School) was placed on the north-facing main facade of the building, at a height of about 8 meters from Bukowska Street.

In September 2013, a thorough renovation of the auditorium was conducted, including the replacement of the parquet floor, installation of wainscoting, and repainting of the walls.

On 18 April 1929, a commemorative plaque by the same author was unveiled, dedicated to the late first school principal, Antoni Borzucki, who passed away the previous year.

[4][12] On 14 May 2005, one of the two Poznań monuments to Karol Marcinkowski, designed by Wiesław Koronowski, was unveiled in front of the main entrance.

On 11 May 2013, another commemorative boulder by Wiesław Koronowski and Jarosław Bogucki was unveiled, dedicated to Jan [pl] and Stanisław Kasznica – Marcinek graduates and soldiers who fought in World War II.

[30] From October 1928 until the outbreak of World War II, the school published a monthly magazine called Orlęta, which eventually gained a national character and began to be subscribed to abroad.

[31] Since 2001, the school has been annually organizing the Marcinek Theatre Festival in Poznań, attracting theaters from all over Poland and abroad.