Bennett was born in Cardiff on 1 December 1968. His mother was a Cardiff supply teacher and his father worked at the GKN steelworks as a a quality control inspector.
Bennett was educated at Llandaff City junior school and Radyr Comprehensive. He swam competitively for City of Cardiff Swimming Club, and was later a member of Cardiff Amateur Athletics Club. He represented South Glamorgan in both sports.
After leaving school, he worked as a shop assistant at a video rental store before going to Middlesex Polytechnic to study sociology. However, he dropped out midway through the course.
Returning to Cardiff, he did a one-year journalism course at Cardiff Institute of Higher Education, then worked as a newspaper reporter at the Carmarthen Journal in West Wales (1992-96). Leaving journalism, Bennett then undertook a wide array of jobs over the next 15 years, including administrator, call centre operative, English teacher (in China and South-East Asia), property developer, painter and decorator, pub barman and general building labourer.
Bennett began his writing activities by co-founding and editing the Cardiff City Football Club fanzine O Bluebird of Happiness (1989-92). Later he co-wrote four books for the History Press with fellow Cardiff City diehard David Collins: Never Mind the Bluebirds (The Ultimate Cardiff City Quiz Book), Never Mind the Bluebirds 2 (Another Ultimate Cardiff City Quiz Book!), The Secret Premier League Diary of a Cardiff City Fan and The Little Book of Cardiff (a local history book) between 2012-15.
Politically, Bennett began on the left, joining the Trotskyist Workers Revolutionary Party (WRP) at the age of 16. He left after six months. He was later active in the Labour Party (1992-96), before eventually abandoning the left – and even the centre-left – in disgust at its embrace of mass immigration.
This led to Bennett joining UKIP in 2014. He campaigned in the 2014 European election, and was then agent for UKIP candidate Brian Morris in Cardiff West at the 2015 general election. He became secretary, and then chairman, of the Cardiff UKIP branch, and then joined the UKIP Wales regional committee.
In March 2016, it was reported that Bennett had topped the poll in the South Wales Central region in a ballot of all UKIP party members in Wales to select Welsh Assembly candidates. He was almost immediately caught up in a media storm over controversial remarks regarding rubbish problems in Cardiff’s City Road area, which Bennett blamed on students and – controversially – Eastern European immigrants. This led to senior UKIP party leaders, like Nigel Farage and Immigration spokesman Steven Woolfe, publicly distancing themselves from Bennett. A petition containing the names of 16 other UKIP Assembly candidates opposing Bennett’s candidacy was presented to the party’s National Executive Committee (NEC) – which promptly re-selected him as lead candidate. He was duly elected to the Assembly on 5 May 2016.
This furore also involved the resignation from the list of the number two UKIP candidate in South Wales Central. This was Alexandra Phillips, former personal aide to Nigel Farage, whom Bennett alleged was plotting to get rid of him in her role as Assembly campaign media officer.
In the Assembly UKIP group, he backed Neil Hamilton for leader over Nathan Gill, whom he held responsible for the deselection campaign against him. After Hamilton became leader of the group, Bennett was appointed as UKIP Assembly spokesman for Local Government, Housing and Sport.
He is a member of the Equalities, Local Government and Communities Committee and the Petitions Committee.