Note: Brisbane played its "home" final at the MCG despite being ranked above Geelong due to the agreement then in place with the Melbourne Cricket Club that at least one game each week of the finals be played at the MCG.
Week four
This was the first grand final in the history of the AFL to be played by two non-Victorian teams; Port Adelaide's first; and the Brisbane Lions' fourth consecutive.
Match attendance
Total match attendance for all games was 5,915,407. Attendance at the grand final was 77,671. The largest non-finals attendance was 60,898 people for the Collingwood v Carlton game in round 22. Attendances during the season were affected by the ongoing reconstruction of the Ponsford, Olympic and Melbourne Cricket Club stands at the MCG to be ready for the 2006 Commonwealth Games.
won its first ten matches of the season, which was at that time the longest winning streak in its history. This record stood until 2009, when the Saints won 19 games in a row.
A five-minute brawl broke out between rivals Hawthorn and Essendonin the round 11 match, after which one Bomber and four Hawks players received suspensions totalling 16 matches, and a combined total of $70,700 of fines were handed out. 27 charges were brought before the AFL Tribunal, the most ever from a single game. The game is widely known as the "Line in the Sand" match as the brawls were sparked in the third quarter after Hawthorn players were urged at a half-time address by club legend Dermott Brereton to metaphorically draw such a line; Brereton thought the young Hawks were being physically intimidated by the more experienced Bombers.
In round 13, defeated the for the first time since the merged club was established in 1997. The win broke a 10-game winning streak for Brisbane against Geelong.
After the round 13 win over the, coach Gary Ayres was told by the board of directors that his contract would not be renewed for the next season, but would be allowed to coach the rest of 2004. Ayres subsequently resigned on the same day, without shaking hands or a word with the media. He was replaced by Neil Craig at first on a temporary basis, but then got the job permanently for 2005 and onwards.
During the round 19 match between and the, Sydney head trainer Wally Jackson suffered a fatal heart attack during the last quarter. Most of the Sydney players were upset and distracted as Jackson was given CPR on the interchange bench; and despite Sydney having led the Kangaroos by 40 points at three-quarter time, they faded to lose by six points.
On Saturday, 28 August 2004, the Brisbane Lions set the VFL/AFL record for having the most experienced team in history. The 22-man Brisbane squad had collectively played 3,740 senior career games, and had collectively scored 3,399 senior career goals. Only four of the 22 players had not played over 100 AFL games; Jonathan Brown, Robert Copeland, Dylan McLaren and Richard Hadley.
With its round 22 win over Adelaide, clinched its third consecutive minor premiership, a feat achieved by only two other clubs in the previous 50 seasons. This would later prove crucial in relation to home ground advantage at the preliminary final stage.
Despite earning a home preliminary final by beating St Kilda two weeks earlier, the Brisbane Lions were forced to play Geelong in Melbourne at the MCG, due an agreement between the AFL and the MCG to play at least one match per week at the ground in finals. This contractual stipulation was removed following renegotiation the following season.