Chasing Great, released in cinemas in September, will feature never-before-seen footage of McCaw including his friends and family, TVNZ reported.
''I was always quite keen to make sure I kept some of the private stuff private, not for any reason other than I just felt that was the right thing to do,'' McCaw told TVNZ.
He said the opportunity to ''inspire some young kids'' prompted him take part in the project, TVNZ reported.
The film, directed by Michelle Walshe and Justin Pemberton also features a cover of the track 'Everybody wants to rule the world' by Lorde.
''This is a film for New Zealanders young and old, it will really connect with anyone interested in what it takes for an ordinary person to achieve phenomenal accomplishments,'' Ms Walshe told TVNZ.
The film opens in cinemas on September 1.
