[3][4] Barrett got his big break in June 2014 when he was named in a Crusaders side shorn of its international players who played a midweek match against the touring England national team.
[5] The result did not turn out as Barrett would have liked, however when the Super Rugby season resumed following the mid-year internationals he gained his first full cap for the Crusaders.
Injuries to international second-row forwards Sam Whitelock and Luke Romano saw Barrett named on the replacements bench for the match against the Blues on 5 July 2014.
Barrett came on as a substitute early in the second half for Jerome Kaino who had been selected to unusually start at lock following injury to Sam Whitelock and Brodie Retallick, as well as Luke Romano returning home due to family bereavement.
Barrett returned to action after missing the first Bledisloe Cup test and replaced blindside flanker Liam Squire off the bench in the second of the series.
Barrett started another two times that year, against Australia and against the Barbarians due to Retallick not playing rugby for the rest of 2017 for personal reasons.
Barrett went back to his regular role on the bench against France, a French XV and against Wales on the 2017 end-of-year tour, having made 14 appearances for the All Blacks after the season finished, including every single test but two.
Barrett finished off the Steinlager series by winning the award for Man of the Match, after an outstanding defensive performance, as the All Blacks won against France 49–14.
[9] Barrett became only the fourth New Zealander in the history of international rugby to be sent off during a test, joining team mate Sonny Bill Williams, amongst others.
On 28 August, All Blacks Head Coach, Steve Hansen named Barrett, as well as both of his brothers, amongst the 31 players in New Zealand's squad for the 2019 Rugby World Cup.
But with England fielding two openside flankers in their starting lineup, Barrett was subbed off at half-time in the semi-final, with New Zealand eventually losing 7-19.