The Pensioners also suffered from bad luck in the FA Cup, a scheduling conflict forcing them to play a mostly amateur reserve side against non-league Crystal Palace, losing 7–1 in the Third Qualifying Round.

Scottish international John Robertson was hired as the club's first player-manager, a half-back who would go on to score Chelsea's first competitive goal in a 1–0 win against Blackpool.

After this, the club recruited many established players from other teams, including 22 stone goalkeeper William "Fatty" Foulke previously of Sheffield United, and forward Jimmy Windridge who came from Small Heath.

Chelsea's first ever league campaign began on 2 September with a trip to Cheshire to face Lancashire Combination champions Stockport County at Edgeley Park.

The match was a tight affair against a side with previous experience in the second tier, with County having an Ashton Schofield penalty saved by Chelsea goalkeeper Bill Foulke only for George Dodd to put the ball in from the rebound with half an hour to play to give the hosts two points.

[3] Two days later, Chelsea played their first ever home league match against newly elected Hull City, with the Blues romping to a 5–1 win.

[4] On 16 September Chelsea made their way to the West Riding of Yorkshire where they drew 1–1 with Bradford City, who had only switched codes from rugby league two years prior.

Playing 6 games and winning 4 of them, Chelsea ended the month with 9 points and in 3rd place, showing very promising form and exhibiting clear potential to mount a strong promotion push in their début season.

Stanley gave the soldiers a consolation in the 50th minute, however Jimmy Windridge later scored a brace give to Chelsea a wider winning margin.

[9] However their seven match unbeaten run in all competitions came to an end on 21 October with the visit of Chesterfield Town to Stamford Bridge, the winner coming from Joe Ball in the 55th minute for a 1–0 win over the Blues.

Furthermore, defender Bob Mackie kept a clean sheet whilst deputising for Foulke, registering the club's first ever in the FA Cup[11] Two days later, Chelsea suffered their second consecutive league defeat at the hands of Burslem Port Vale at the Athletic Ground in Staffordshire, the Valiants went two goals up via George Price and Harry Croxton in the 9th and 51st minutes respectively.

To add to the Pensioners' humiliation, to this day, this defeat is the largest win a non-league side has ever registered against league opposition in the FA Cup.

[18] Chelsea kept up their good form with a 3–0 defeat of Burton United at Stamford Bridge on 2 December, Jimmy Robertson getting the first goal in the 20th minute with McDermott and Moran adding a second and third respectively.

[19] On 9 December, Chelsea narrowly defeated Grimsby Town 2–0 at Stamford Bridge, with two late goals coming from Tom McDermott and Jack Kirwan in the 80th and 85th minutes respectively, with Bob McRoberts also having a penalty saved.

[24] Chelsea ended 1905 on a high with a 4–2 win at Stamford Bridge against Stockport County on 30 December, despite falling behind to a Pass goal after a quarter of an hour.

[25] The Pensioners began 1906 just as they ended 1905, keeping up their 12-game unbeaten run in the league with a 6-0 hammering of Blackpool on 6 January at Stamford Bridge.

[27] Chelsea played their first away match of the year at The Hawthorns against West Bromwich Albion being held 1-1, ending their 4-game winning streak.

Pearson's goal in the 1st minute clearly emphasised Chelsea's intent to put the previous week's result behind them, however Martin equalised for Lincoln.

Despite this setback, McDermott and George Key gave Chelsea a secure lead before McRoberts tucked away a penalty with 10 minutes to go to make it 4.

[35] However, Chelsea's purple patch came to an abrupt end with a disappointing 2–0 defeat to Burnley at Turf Moor on 24 March, with the Clarets securing the win through two first-half goals from Bell and R Smith in the 11th and 21st minutes respectively.

[36] Chelsea bounced back from that defeat with a 4–0 rout of Leeds City on 31 March at Stamford Bridge, with Pearson getting the opener after half an hour and McRoberts doubling the Blues' led through a penalty in the 40th minute, with McDermott later added a third and Windridge scoring the fourth with a quarter of an hour left to round off the scoring.

Chelsea could ill afford any more slip ups going into the final month of the season as the promotion race between the Blues, Bristol City and Manchester United began to reach its critical stage.

On 13 April Chelsea played promotion rivals Manchester United at Stamford Bridge in a make or break match for both sides.

[39] However, Bristol City won their match against Gainsborough Trinity, taking advantage of the draw between their closest rivals to increase their lead at the top, whereas West Bromwich Albion suffered another heavy defeat, this time to Barnsley, all but ending their promotion hopes.

For a third match in a row Chelsea failed to win, drawing 0–0 at home with Glossop, whereas Manchester United defeated Gainsborough Trinity to establish a 3-point lead over the Blues, putting their promotion hopes in serious jeopardy as they still had a game in hand over them.

Thus Chelsea, who began April with a strong chance of promotion completely faded away, failing to win four matches in a row, condemning themselves to a 3rd-place finish, and another season in the second tier.

In their final match of the season on 28 April, Chelsea travelled to Ashton Gate to face newly crowned champions Bristol City.