After beginning his career in his home country, he went on to have successful spells in the Netherlands and England, winning the Champions League with Liverpool in 2005 and appearing in 186 official matches for the club over six seasons.

[6] Dudek left his country in 1996 at age 23, joining Feyenoord, but had to wait a year before he made his debut, proceeding to appear in all Eredivisie matches the following four campaigns.

Dudek was a catalyst in Liverpool's 2005 Champions League victorious run, performing a double save against AC Milan's Andriy Shevchenko at the end of extra time in the final, after the team had rallied from a 3–0 deficit to tie the match 3–3.

He saved from Andrea Pirlo and Shevchenko in the ensuing penalty shootout, won 3–2, where he attempted to distract the opposing players with the "spaghetti legs" tactic that was used by former Liverpool goalkeeper Bruce Grobbelaar in the 1984 European Cup final.

[19][20][21] A group of Liverpool fans, "The Trophy Boyz", recorded a novelty tribute single called "Du the Dudek", which became a top-40 hit in the United Kingdom;[22] profits from the sale of the track went to the family of Michael Shields, a club supporter who was imprisoned in Bulgaria in controversial circumstances following the match.

[25][26] In a poll conducted by UEFA.com, Dudek's double save from Shevchenko was voted the greatest Champions League moment of all time, ahead of Zinedine Zidane's left-footed volley against Bayer Leverkusen in the 2002 final and Ole Gunnar Solskjær's injury-time winner against Bayern Munich in 1999 for Manchester United.

[29] In Juande Ramos' first match as Madrid manager, in December 2008, Dudek was handed a rare start in a 3–0 home defeat of Zenit Saint Petersburg as the club was already qualified from the Champions League group stages.

This performance earned glowing praise from the manager, who highlighted the goalkeeper's qualities and referred to him as a "magnificent player";[30] it would be his last appearance of the campaign, which also saw a 5–0 aggregate loss against former club Liverpool in the round of 16.

[31] On 27 October 2009, Dudek saw his first action of the campaign in the first round of the Copa del Rey, in a 4–0 shock loss to minnows Alcorcón from Segunda División B, with the goalkeeper being one of the few on the losing end to perform well.

[35] On 10 April 2010, following news of the air crash which claimed the lives of 96 Polish people – including President of Poland Lech Kaczyński and several top government officials – the players of both Real Madrid and Barcelona agreed, at Dudek's request, to observe a minute's silence for the evening's El Clásico match.

[37] As manager José Mourinho was appointed, he worked with his fourth coach in as many seasons; on 30 November, he was fined €5,000 for his role in the controversial sendings-off of teammates Xabi Alonso and Sergio Ramos in the Champions League group stage match against Ajax.

He also played in seven of his country's ten qualifying matches for the 2006 World Cup, but owing to a lack of appearances at club level during the season, he was dropped from the starting line-up in favour of Artur Boruc and left off the final squad as a result.

[43] Dudek's omission from the World Cup squad was greeted with shock among Polish fans and media alike, with one newspaper's headline reading: "Has Janas [national team manager] gone mad?!"

During a warm-up match against Colombia, where both Boruc and Tomasz Kuszczak were at fault for each of the goals in a 1–2 home defeat, the angered Polish fans started to chant Dudek's name as a reminder of what they perceived as a mistake by Janas to drop him.

[44] Following the World Cup, Dudek returned to the national team to play in two fixtures under new boss Beenhakker, a 2–0 friendly defeat in Denmark and a 1–3 UEFA Euro 2008 qualifying loss against Finland at home, before being dropped yet again.

In a match which was played in heavy snow and in front of a near-empty Stadion Śląski in Chorzów, he was denied a clean sheet by an own goal from Seweryn Gancarczyk in a 0–1 defeat.