At the beginning of the 21st century, Legia Warsaw II played between the III and IV liga. After the 2006–07 season, the reserve team was withdrawn from the league,[5] giving way to the Młoda Ekstraklasa team, which had its own separate competition.[6] In 2013, after the elimination of this competition, Legia II returned to III liga.[6]
Despite the existence of the Młoda Ekstraklasa, Legia's reserves continued to compete in the Polish Cup at the regional level. In the 2007–08 season, Legia II reached the final of these games, losing 0–1 to Hutnik Warsaw.[7] However, thanks to the participation in the finals, the reserve team got the right to start in the competition at the central level in the next season, where it ended its adventure in the first round.[8] In the 2011/2012 season, the reserves of the Warsaw club won the Polish Cup at the provincial level, defeating Broń Radom 2–1 in the final.[9] In the next season, they started again in the central level competitions, also reaching the first round.[10]
In the 2019–20 season, Legia II reached the 1/8 finals of the Polish Cup (previously eliminating higher-ranked teams of Wigry Suwałki and Odra Opole), where they were defeated by Piast Gliwice (0–2).[11] All the games were held at the Ząbki City Stadium (then the home for Legia II games).[11]
On 15 June 2022, Legia II defeated Legionovia Legionowo 1–0 and won the Mazovian Polish Cup, thus qualifying for the central tier of the cup in the 2022–23 season.[12] On 30 August 2022, it lost in a home first round match against Wisła Kraków 0–5 and dropped out of the competition.[13] In the 2022–23 season, Legia II successfully defended the Polish Cup at the Mazovian level, winning 3–0 against Pogoń Grodzisk Mazowiecki in the final.[14] In the first round of the central level competition of the 2023/2024 campaign, on 27 September 2023, it unexpectedly eliminated Ekstraklasa club Ruch Chorzów. In the next round, after overtime, it suffered a loss to another representative of Poland's top league, Korona Kielce, effectively dropping out of the competition in the 1/16 finals.[15]