Joseph was born in Hawke’s Bay and grew up in the country.

Joseph left school without any qualifications and later went to university, obtaining an honours degree in Law. He graduated from university on the same day as his youngest sister, the first in their family to do so.

Living in Queenstown, Joseph became a senior trial lawyer and built his own law practice, appearing in courts throughout the South. 

In 2017 he was appointed by the Deputy Solicitor General to the Crown Prosecution Panel for the Invercargill Crown Solicitor. Joseph has also been appointed by the Court as a Youth Advocate.

Joseph was National's candidate for the Southland Electorate seat at the 2020 New Zealand General Election, winning the seat by a majority of 5,645 votes.  He has again been confirmed as National's candidate for the Southland Electorate for the 2023 election.

Joseph is the National Party Spokesperson for the Space, Forestry, Treaty Negotiations and Tourism portfolios. He is also the Associate Spokesperson for Agriculture.

He is a member of the Primary Production Selection Committee and the Parliamentary Service Commission Artworks Committee.

Joseph has been an Army reservist and volunteer firefighter.

He has three children with his wife Silvia. In his spare time he likes to ski, mountain bike, and spend time with his family.