[7] Walter Leigh, the team's top goalscorer of the previous season, moved on, joining Clapton Orient,[10][11] newly elected to the Football League Second Division.

[12] The club's first match of the season, on 2 September, was away to Queens Park Rangers; Floyd, Phillips, Sheridan and Marriott all made their Southern League debuts for New Brompton.

[13] Queens Park Rangers scored two goals in each half to win 4–0; the correspondent for The Daily News stated that the home team were "the better side at every point" and well deserved their large victory.

[14] The first Southern League game of the season at New Brompton's ground, Priestfield Road, a week later against Bristol Rovers, resulted in a 3–0 win for the away team.

[13][15] Phillips scored New Brompton's first Southern League goal of the season on 16 September and the team achieved their first victory, beating Northampton Town 2–0,[13][16] before losing again in their next game, a 4–0 defeat away to Portsmouth.

[22] The team's winless run continued for the rest of the month as they drew with Plymouth Argyle and Southampton and lost to Reading.

[13] On Christmas Day, New Brompton beat Brighton & Hove Albion 1–0; Campbell scored the winner from a penalty kick, his first goal for the club.

[13] New Brompton ended 1905 with a 2–0 home defeat to Queens Park Rangers; John Martin, normally a full-back, played as goalkeeper in place of Fred Griffiths.

[13][26] The reporter for the Athletic News wrote that on the whole New Brompton played as well as their opponents but that their forwards "proved quite incapable of turning to account the many openings which fell their way".

[13] New Brompton's next game drew an attendance reported at 5,500, the largest of the season at Priestfield Road; the Athletic News attributed the large turnout to "the recent smart performances of the local eleven".

[13] The team's winless Southern League run extended to four games with defeats away to Luton Town on 17 February and Brentford on 3 March.

Paddy Travers scored the only goal to give his team what the Daily Telegraph's reporter described as their best result of the season; the writer praised the New Brompton defence as "very sound".

[34] Their next two games resulted in goalless draws against Brighton & Hove Albion and West Ham United;[13] the Athletic News was again critical of New Brompton's forwards against West Ham, saying that the team's "lack of success was mainly due to the inability of their front line to accept the gifts which the fortune of the game offered".

New Brompton entered the 1905–06 FA Cup at the first-round stage, where they played at home to fellow Southern League Division One club Northampton Town.

[39] In the second round, New Brompton played at home to another Southern League Division One team, Southampton; the match finished 0–0, necessitating a replay at the Dell.