During the 2004–05 English football season, Gillingham F.C. competed in the Football League Championship, the second tier of the English football league system. It was the 73rd season in which Gillingham competed in the Football League and the 55th since the club was voted back into the league in 1950. It was Gillingham's fifth consecutive season in the second tier of the English league system, to which the club had gained promotion for the first time in 2000.

Gillingham began the season with two victories in their first three games, but results rapidly declined thereafter. Between early September and late November, the team won only once in 14 games, leaving them in 23rd place in the 24-team league table. After a 4–1 defeat to Crewe Alexandra on 20 November, Andy Hessenthaler resigned as the team's manager, a position he had held since 2000. Stan Ternent took over as manager in early December and results improved slightly, but at the end of 2004 the team were still within the bottom three places which at the end of the season would result in relegation to the third tier of English football. In the last 15 games of the season, Gillingham only lost twice, but the run included 9 draws. Going into the final game of the season, Gillingham were in 21st place in the table and could still be relegated. A 2–2 draw against Nottingham Forest, combined with the results of two other games, meant that Gillingham finished in 22nd place and were relegated, ending a five-season spell in the second tier.

The club also competed in two knock-out tournaments, but in both the FA Cup and the Football League Cup they were eliminated at the earliest possible stage. Gillingham played 48 competitive matches, winning 12, drawing 14, and losing 22. Darius Henderson was the team's top goalscorer with 9 goals. Paul Smith made the most appearances, playing 43 times. The highest attendance recorded at the club's home ground, Priestfield Stadium, was 10,810 for the final home game of the season against Cardiff City.

Background and pre-season

The 2004–05 season was Gillingham's 73rd season playing in the Football League and the 55th since the club was elected back into the League in 1950 after being voted out in 1938. In the 1999–2000 season, Gillingham beat Wigan Athletic in the Second Division play-off final to reach the second tier of the English football league system for the first time in the club's history. In the team's first three seasons at this level, they finished in mid-table, ending the season in 13th place out of 24 teams in the 2000–01 season, 12th in 2001–02, and 11th in 2002–03. In the 2003–04 season, they finished in 21st place, level on points with 22nd-placed Walsall, avoiding relegation to the third tier only because their goal difference of −19 was one better than Walsall's −20.

At the start of the 2004–05 season, Andy Hessenthaler was the team's player-manager, a position he had held since 2000. Wayne Jones retained his position of first-team coach from the previous season, and he was joined by a second coach as the club signed Iwan Roberts, a veteran forward who had been released by Norwich City after seven seasons, to a player-coach position. Gillingham further boosted their attacking options by signing another forward, Darren Byfield, who had last played for Sunderland. Rod Wallace, a forward who had spent two injury-hit seasons with Gillingham, was released by the club and left professional football altogether. After playing in a blue and black kit during the previous season, the club switched to blue shirts with white sleeves, blue shorts, and blue socks. The change kit, to be worn in those away games where there was a clash of colours with the home team, was all yellow.

Before the new season, the second tier of English football, previously called the Football League First Division, was renamed the Football League Championship. Previewing the season, The Sunday Telegraph reported that a leading bookmaker gave Gillingham odds of 200/1 of becoming champions of the division, the longest of any team; the newspaper noted that Gillingham "face[d] a hard season" but that they might "hang on to live another day". Writing in the matchday programme for the first home game of the season, Hessenthaler said "we've already been told by one paper that we are going to finish 23rd [...] we have proved them all wrong over the last four years and we'll do it again this year".

Football League Championship August–December

Gillingham's first match of the season was away to Ipswich Town; both Byfield and Roberts made their debuts. Midway through the first half, Byfield passed the ball to Paul Smith, the team's captain, who scored Gillingham's first goal of the campaign, but Ipswich scored twice to win the game. Hessenthaler described both the goals which his team had conceded as "sloppy". Gillingham's first game of the season at their home ground, Priestfield Stadium, was against Leeds United, who had been relegated from the top-tier FA Premier League at the end of the previous season after 14 years at the highest level of English football. The attendance of 10,739 was the largest for a game at the stadium since the previous September. Byfield scored a goal within the first five minutes and Roberts added a second; Leeds scored in the second half but Gillingham held on for a 2–1 victory. Hessenthaler told the press "For endeavour, desire and commitment I thought we were tremendous. If we do that every game we won't be in the bottom three like everyone expects us to be this season." Four days later, the same two players scored in another 2–1 victory over Preston North End; Mark Saunders suffered a broken leg and would not play again during the season. After losing to Stoke City and Queens Park Rangers without scoring a goal in either game, Gillingham finished August with a 2–1 victory over Burnley, in which Roberts and Byfield once again scored the goals, leaving them 10th in the Championship league table.

Gillingham's first match of September ended in a 4–0 defeat to Sunderland at Priestfield; Hessenthaler was again critical of his team, telling the press "It was schoolboy defending for their goals and that's not acceptable." Patrick Agyemang scored twice to secure a 2–2 draw away to Coventry City on 15 September, but Gillingham lost their next seven games. The run began with a 3–1 defeat away to Reading; Dave Kitson, whom Gillingham had tried unsuccessfully to sign during the previous season, scored a hat-trick for Reading in the first half of the game. Gillingham lost home games to Brighton & Hove Albion and Leicester City without scoring a goal and finished September in 20th place in the league table, one point above the bottom three positions which would result in relegation to League One at the end of the season. Darius Henderson, a forward who had joined Gillingham in January but suffered a serious injury in only his sixth game for the team, played for the first time since March in the defeat to Leicester. Roberts was absent from the team for the whole of October; three of the games he missed were the result of a suspension issued by the Football Association, the governing body of the sport in England, after the publication of an autobiography in which he contended that he had deliberately injured an opposing player during his time at Norwich. When he returned, he was unable to regain his place in the starting line-up and was used almost exclusively as a substitute. Henderson scored his first goal of the season to give Gillingham the lead over Plymouth Argyle on 2 October, but Plymouth scored twice in the final minute of the game to win 2–1. On 17 October, Sheffield United had what BBC Sport called a "comfortable win" over Gillingham at Priestfield; Paul Shaw, who had left Gillingham during the previous season, scored twice against his former club in a 3–1 victory. Gillingham followed this with two defeats away from home, 3–1 to Millwall and 2–1 to West Ham United, after which they were in 23rd place in the table. Mark Hodgkinson of The Daily Telegraph wrote that in the game against West Ham, Gillingham were "so short of self-belief that they were delighted at conceding just the three goals".

Although Gillingham ended their losing run with a 1–0 victory at home to Wolverhampton Wanderers on 30 October, thanks to the first senior-level goal scored by the teenager Matt Jarvis, they remained in 23rd place in the league table, above only Rotherham United, who had yet to win a league game during the season. Gillingham kept a further two clean sheets in their first two games of November, securing 0–0 draws against Watford and Sheffield United, two teams in the top half of the table, but remained in the bottom three places themselves. They failed to score again at home to Derby County on 13 November, losing 2–0. A week later, they lost 4–1 away to Crewe Alexandra; three days later, Hessenthaler resigned as manager, but was retained as a player. John Gorman, who had been appointed assistant manager the previous month, took over as caretaker manager. He resigned a week later, after overseeing a 2–1 victory over Nottingham Forest, to take the manager's job at Wycombe Wanderers. Roberts, Smith, and the club's youth team coach Darren Hare were collectively put in charge for the next game, a 3–1 defeat to Cardiff City on 4 December. Three days later, the club appointed Stan Ternent as manager on a two-and-a-half-year contract. Ternent, who had more than 25 years of managerial experience, had been dismissed as manager of Burnley six months earlier. His first game in charge ended in a 2–0 defeat to Wigan Athletic, but a week later Gillingham gained their first win under his leadership with a 3–1 victory over Rotherham United. On 26 December, Gillingham took the lead over Brighton & Hove Albion but conceded two goals in the final 12 minutes of the game and lost 2–1. Gillingham's last game of 2004 was a 3–1 victory over Coventry City on 28 December; Ian Cox became only the second Gillingham player of the season to score two goals in a game. Despite the victory, Gillingham remained in the relegation places at the end of the calendar year.

January–May

Gillingham began 2005 with a goalless draw at home to Reading in a game played in very poor conditions on New Year's Day. Two days later, they held Sunderland, who were in third place in the table, to a 1–1 draw; after failing to beat their struggling opponents, the Sunderland team were booed by their own supporters. After the game, Ternent told the press "With the injuries we have, this is a satisfactory result. Hopefully eight more wins can keep us up." Gillingham continued their unbeaten league run with a 1–1 draw with Plymouth Argyle, but then lost 2–0 to Leicester City on 22 January. Hessenthaler, who had been included in the starting line-up only twice since resigning as manager, made his final appearance of the season against Leicester; days later he joined Hull City on a three-month loan. Michael Flynn, a midfielder newly signed from Wigan Athletic, made his debut against Watford on 5 February, which ended in Gillingham's second consecutive 2–0 defeat. A goalless draw with Millwall a week later meant that Gillingham had scored only two goals in six league games in 2005 and remained in the relegation places. Henderson scored the team's first goal for over a month on 19 February away to Wolverhampton Wanderers, and it appeared that Gillingham had won when Flynn gave them a 2–1 lead in the 90th minute, but the home team scored in injury time to secure a draw. Ternent was unhappy about the late goal, telling the media "First of all there was a foul on our centre-back and then the lad has handled it. Sometimes you need a bit of a break to go your way, a break that makes all the difference, and things haven't been going for us lately."