In 2012 he won the New Zealand International Science Festival 'Science Idol' competition after creating a parody of a Justin Bieber song.
[4][5] The same year he made a Kony 2012 parody on YouTube which won a competition by the Otago School of Business.
[10] In 2015 he released a song about the show, named "Hold Your Hand in Mine Harry Warner".
[15][16] In 2022 Mustapic launched the show Abandonment Issues, in which he tracks down New Zealand celebrities who have decreased in popularity,[17] focussing on iconic television moments of the 2000s.
[18] In 2023 Mustapic hosted the television show Queer Academy, which was written and directed by Re: News.
[23] In 2024 Mustapic launched the comedy television show James Must-a-pic His Mum a Man in which he puts his single mother, Janet, on dates.
[3] The programme features other well-known individuals such as entertainer Suzy Cato and comedian Ray O'Leary.
[3] His father made a complaint to the Broadcasting Standards Authority against TVNZ, saying that the show unfairly represented him and breached his privacy.