| 1885 |
Founded as Millwall Rovers |
| 1894 |
Changed name to Millwall Athletic |
| 1899/1900 |
F.A. Cup semi-finalists |
| 1902/1903 |
F.A. Cup semi-finalists |
| 1903 |
Dropped "Athletic" from the club name |
| 1910 |
Moved to The Den |
| 1920/1921 |
Founder member of Division Three South |
1927/1928
|
Division Three South champions
Promoted to Division Two
|
| 1933/1934 |
Relegated to Division Three South |
| 1936/1937 |
F.A. Cup semi-finalists |
1937/1938
|
Division Three South champions
Promoted to Division Two
|
| 1947/1948 |
Relegated to Division Three South |
| 1952/1953 |
Division Three South runners-up |
| 1958/1959 |
Placed in Division Four on League reorganisation |
1961/1962
|
Football League Division Four champions
Promoted to Division Three
|
| 1963/1964 |
Relegated to Division Four |
1964/1965
|
Division Four runners-up
Promoted to Division Three
|
1965/1966
|
Division Three runners-up
Promoted to Division Two
|
| 1974/1975 |
Relegated to Division Three |
| 1975/1976 |
Promoted to Division Two |
| 1978/1979 |
Relegated to Division Three |
1984/1985
|
Division Three runners-up
Promoted to Division Two
|
1987/1988
|
Division Two champions
Promoted to Division One
|
| 1989/1990 |
Relegated to Division Two |
| 1990/1991 |
Not promoted after play-offs |
| 1992/1993 |
Division Two renamed Division One |
| 1993 |
Moved to The New Den |
| 1993/1994 |
Not promoted after play-offs |
| 1995/1996 |
Relegated to Division Two |
| 1999/2000 |
Not promoted after play-offs |
2000/2001
|
Division Two champions
Promoted to Division One
|
| 2001/2002 |
Not promoted after play-offs |
| 2003/2004 |
F.A. Cup runners-up |
| 2004/2005 |
Division One renamed Football League Championship |
| 2005/2006 |
Relegated to League One |
| 2008/2009 |
Not promoted after play-offs |
2009/2010
|
Promoted to the Championship
after winning play-offs
|