[1] After travelling overseas and working as a bus driver, he began a journalism course and before completion was hired by TVNZ as a researcher.

[1][2] Sainsbury began a 30-year association with TVNZ in 1981 when he was hired as a researcher for the then-weekly current affairs programme, Close Up.

In 1987 he spent a year working with Barry Soper at Independent Radio News, based in the Parliamentary press gallery.

[2][4] In 2007, he succeeded Susan Wood as host of Close Up, which was at that point a daily current affairs programme and the successor to the Holmes show.

[7] In February 2016, Sainsbury returned to daily broadcasting as the weekday morning host on Radio Live, replacing Sean Plunket.