After being the top scorer in the third and second tiers of Polish football with Znicz Pruszków, Lewandowski moved to top-flight Lech Poznań, helping the team win the 2009–10 Ekstraklasa.

In 2015, while playing for Bayern, he scored five goals in less than nine minutes against VfL Wolfsburg, the fastest by any player in Bundesliga history as well as any major European football league for which he was awarded four Guinness World Records.

[20][23] Earlier that month, Lewandowski's agent Cezary Kucharski offered him to his former team Sporting Gijón, which had been promoted to the La Liga, Spain's first division, after ten years in the Segunda División.

[24] He debuted for Lech on 17 July 2008 as a substitute in the first qualifying first leg match of the UEFA Cup versus Khazar Lankaran from Azerbaijan, in which he scored the only goal of the evening in the 75th minute at the Tofiq Bahramov Republican Stadium.

[25] English coach, Sam Allardyce, said that Lewandowski was about to join Premier League club Blackburn Rovers in 2010, but the volcanic ash clouds caused by the 2010 eruptions of Eyjafjallajökull which suspended all flights in and out of the UK, in addition to other financial worries, prevented the potential transfer.

[34] On 1 October, Lewandowski netted a hat-trick and provided an assist in the club's 4–0 victory over Augsburg, following a disappointing 0–3 loss to Marseille in the UEFA Champions League group stage.

[39] Following the winter break, on 22 January 2012, Dortmund thrashed Hamburg 5–1 to move level on points with leaders Bayern Munich; Lewandowski netted twice and added an assist for Jakub Błaszczykowski in the rout.

[42] On 21 April, Lewandowski provided the assist for Shinji Kagawa's 59th-minute goal as Dortmund won 2–0 over Borussia Mönchengladbach to seal their second straight title.

[citation needed] According to Borussia Dortmund director Michael Zorc, speaking in February 2013, Lewandowski would not be renewing his contract with the club, and would leave either in the summer of 2013 or after the 2013–14 season.

[61] On 25 February 2014, Lewandowski scored twice in the Champions League round of 16 first leg against Zenit Saint Petersburg, becoming Dortmund's overall top scorer in European competition, surpassing Stéphane Chapuisat's 16 goals.

[76] On 1 November, in his first league match against Dortmund, Lewandowski scored in a 2–1 win which put Bayern four points clear at the top of the table while leaving his former club in a relegation play-off place.

[84][85] Although Lewandowski stayed until the end of the match, he didn't participate in the shootout; and tests later confirmed that he had fractured jaw and nose bone, and had a concussion, ruling him out for approximately one week.

[86][87][88] On 12 May, playing in a protective mask, he curled in at the 59th minute in his team's 3–2 home victory against eventual winners Barcelona in the Champions League semifinal second leg, albeit they were eliminated by an aggregate score of 3–5.

[89] With 17 goals in 31 games, Lewandowski was joint-second highest scorer of the Bundesliga season alongside teammate Arjen Robben, behind Eintracht Frankfurt's Alexander Meier.

[95] Lewandowski's five goals in nine minutes was also the fastest in any major European football league since Opta began keeping records, and it ended Wolfsburg's 14-match unbeaten run.

[105] He also started Bayern's comeback with a 73rd-minute header in the second leg of the round of 16 on 16 March, after trailing 0–2 home to Juventus, which Munich eventually won 4–2 after extra time, and 6–4 on aggregate.

[111] Five days later, Bayern defeated Carl Zeiss Jena 5–0 in the DFB-Pokal first round, with the help of Lewandowski's hat-trick during the first half and assist to Arturo Vidal in the 72nd minute.

[148] Lewandowski then became the first player in Bundesliga history to score in each of the opening nine, ten and eleven matches of a season, surpassing the record of eight set by former Borussia Dortmund striker Pierre-Emerick Aubameyang.

[190] On 18 September, Lewandowski scored in his 13th consecutive Bundesliga home match against VfL Bochum, surpassing the previous league record of 12 held by Gerd Müller (October 1969 to April 1970) and Jupp Heynckes (June 1972 to February 1973).

On 21 November, Lewandowski scored a hat-trick against Benfica in a Champions League group stage match, becoming the fastest player to 80 UCL goals, in 100 appearances, edging past the previous record of Lionel Messi.

[222] On 12 October, Lewandowski scored a brace in Barcelona's Champions League fixture against Inter Milan, with his last-minute equalizer securing a 3–3 home draw for the Blaugrana at Camp Nou.

[224] On 8 November, Lewandowski was sent off for the second time in his club career for a foul on David García, later receiving a three-game ban, as Barcelona won 2–1 against Osasuna.

[227] On 16 January 2023, he scored the second goal in the 2023 Supercopa de España final, as Barcelona defeated Real Madrid 3–1 in El Clásico, winning his first title with the club.

[236] On 23 September, he scored a brace to help Barcelona overturn a two-goal deficit in a 3–2 home victory against Celta Vigo, becoming the best scorer in first 50 matches for the club in 21st century, with 35 goals, surpassing the record previously held by Samuel Eto'o.

[citation needed] His debut for the senior national team came on 10 September 2008, three weeks after his 20th birthday, against San Marino where he came on as a substitute and scored a goal in a 2–0 away win in 2010 FIFA World Cup qualification.

[277] In the 100th second of the quarter-final against Portugal at the Stade Vélodrome, he finished Kamil Grosicki's cross to open another 1–1 draw, and again scored in the shootout although the Poles lost.

During the first game against Mexico, he missed a penalty;[287] however, in the second match against Saudi Arabia, he scored his maiden goal at a FIFA World Cup as his Poland won 2–0.

Despite often functioning as a lone-centre forward or as an out-and-out striker, he has also stood out for his work-rate and defensive contribution off the ball, and is capable of dropping into deeper roles on the pitch, in order to create space for teammates with his movement, or surprise defenders by making late and sudden attacking runs into the area.

Lewandowski is an accurate penalty taker and has repeatedly shown coolness and composure on the spot; he is also capable of scoring from long range, and has been known to take free kicks.

[338] In February 2022, Lewandowski condemned the Russian invasion of Ukraine and showed his solidarity with the Ukrainian people by wearing a blue and yellow armband during a Bundesliga match.