[2] He previously played for the Chiefs in Super Rugby[3] and Hawke's Bay in New Zealand's National Provincial Championship.

Retallick has earned frequent comparisons to the late former All Black lock, Sir Colin Meads.

He cemented his place in the side on 14 September 2013, winning the award for Man of the Match against South Africa.

[15] Retallick was selected by head coach Steve Hansen as one of 31 players for New Zealand's squad for the 2015 World Cup after a string of outstanding performances for the All Blacks and the Chiefs.

Retallick was subbed off towards the end of the last Bledisloe Cup test against Australia, on 22 October 2016, in Auckland, following a concussion caused by Dean Mumm elbowing him.

Retallick was selected as one of the 33 players for the All Blacks to face Samoa and the touring British & Irish Lions in 2017.

Retallick did not play in 2017 again, following the previous fixture, however, which was a 57–0 win against South Africa, where he scored his fourth test try, because of personal reasons.

Retallick won the award for Man of the Match, earning him comparisons to late All Black great, Colin Meads.

[21] Retallick finished the season off with a better performance against Italy, where he replaced Scott Barrett off the bench in a 66–3 win.

Retallick was named as the Chiefs' co-captain, alongside his injured All Blacks teammate, Sam Cane.

[22] Although the Chiefs performed poorly throughout the season, Retallick returned from injuries to guide the team to the playoffs.

Retallick scored his fifth test try against Argentina in a scrappy 20–16 win, but was subbed off against South Africa the following week, having dislocated his shoulder during the 16–16 draw.

On 28 August, All Blacks Head Coach, Steve Hansen named Retallick as one of 31 players in New Zealand's squad for the 2019 Rugby World Cup.

After New Zealand lost the semi-final to England, 7–19, Retallick went on to win Man of The Match in the Bronze Final, where they beat Wales 40–17 to claim third place.

[29] On 8 February 2023, it was announced that Retallick would return to Kobelco Kobe Steelers in the Japan Rugby League One competition.