Crosby's family moved from GisbornetoPapamoa in 1966, where they started the Papamoa Beach Resort Holiday Park. After finishing high school, Crosby took up an apprenticeship with the Tauranga Electric Power Board, which later became Trustpower. He travelled and worked overseas from 1978 to 1981; after returning to Tauranga he owned Papamoa Electrical Services and Accolade Homes.[2]
Crosby stood for and was elected to the Papamoa Community Council, which was part of the Tauranga Borough Council, in 1986. Crosby was 30 at the time, which was considered young for a councillor.[4] The 1989 local government reforms saw a merger of local authorities, resulting in the establishment of the Tauranga District Council (renamed Tauranga City Council in 2003). Crosby was elected to Tauranga District Council in 1989 and was re-elected every three years thereafter.
Crosby was deputy mayor to Noel Pope from 1998 to 2001.[5] After Pope's retirement, Crosby sought the mayoralty but was defeated at the 2001 local elections by Jan Beange. In 2004, Crosby defeated Beange and began what would become a twelve-year period as mayor.[2][6][7]
Crosby did not recontest the mayoralty in 2016.[2][4] Instead, he successfully sought election to the Bay of Plenty Regional Council, representing the Tauranga constituency.[6] In 2019, he was elected unopposed.[8]
In August 2020, Crosby was elected as the president of Local Government New Zealand, the national association of councils in New Zealand, succeeding former Dunedin mayorDave Cull. Crosby had previously served as Cull's vice-president.[9]
