Allen became the boss of Brentford in March 2004. His first season was a success, saving the club from relegation from League One. In the 2004/05 and 2005/06 season's he guided the club to the play-offs and he also enjoyed success in The FA Cup, reaching the fifth round in two consecutive years.
After Brentford, Allen became manager of then League Two side Milton Keynes Dons for the 2006/07 campaign. He again enjoyed a successful season taking the club to the play-offs.
He went onto manage Leicester City and Cheltenham Town, where he followed his father's footsteps, as Dennis Allen also took charge at Whaddon Road between 1974 and 1979.
Following his time with Cheltenham, Allen had another spell with Barnet before joining Notts County.
After revitalising Barnet who went onto secure their Football League status, Allen performed a similar role with Notts County, guiding them to League One safety (2010/11).
He later performed similar heroics back at Underhill at the end of the 11/12 season before he joined Gillingham.
He enjoyed great success in his first season in charge by guiding Gillingham to promotion to npower League One. Allen then sealed the League Two title to earn their first trophy in nearly 50 years and was later named the Manager of the Year in the division.
Allen was again Head Coach of Barnet on March 19, 2014, returning to the club where his managerial career began in 2003.
Martin Allen then joined Eastleigh on the 1st December 2016.
During his playing days, Allen played for QPR, West Ham United, Portsmouth, Southend United and he earned two England U21 caps.
Allen played in the 1986 League Cup Final and he was part of the promotion teams of 1991 and 1993 with West Ham United.
Martin is also a graduate of the LMA's Certificate in Applied Management at Warwick University.