Joshua studied at the University of Auckland, in New Zealand, where he earned a Bachelor of Science in Sport and Exercise Science. On graduation he then completed his Graduate Diploma in Secondary Teaching. After a few years teaching in New Zealand, he moved to the UK to teach, and worked at the London Olympics. He then moved to Sweden and worked for 5 years at Internationella Engelska Gymnasiet Södermalm. In 2017, he returned to New Zealand and married his Swedish wife. After 3 years back home, he returned to Sweden, and at the start of 2022, began working at SIS.