He played in the 2008 and 2009 Toyota Cups before signing with the Manly Warringah Sea Eagles for 2010.
2010
In round 12 of the 2010 NRL season, Whare made his NRL debut against the North Queensland Cowboys at 1300SMILES Stadium, scoring three tries in the Sea Eagles 24–20 win, the first time a player has scored three tries in his top-grade debut for the Manly Warringah Sea Eagles. Whare played in 4 matches and scored 3 tries in his debut year in the NRL. At the end of the season, Whare was selected for the Junior Kiwis.
In 2012, Whare divided his playing time between the Manly Warringah Sea Eagles NRL side, and the New South Wales Cup. This was due to Manly's established backline which included representative players Brett Stewart, Steve Matai, team captainJamie Lyon, Jorge Taufua and David Williams. Becoming something of a "Mr Fix-it" for the Sea Eagles when called into the top grade, Whare played in the centres, on the wing, and at fullback during the season. On 30 May 2012, Whare announced that he had signed for the Penrith Panthers from 2013, citing the opportunity to establish himself as one of the NRL's top centres. Despite expressing a desire to stay at Manly beyond 2012, Whare felt his opportunities to play centre was limited at Manly due the presence of club co-captain Jamie Lyon and Kiwi international centre Steve Matai. Whare finished the 2012 NRL season with playing in 21 matches and scoring 6 tries for the Sea Eagles. Whare was selected to make international debut for New Zealand against Australia in the October test at 1300SMILES Stadium. Whare played at centre in the Kiwis 12–20 loss.
2013
In round 1 of the 2013 NRL season, against the Canberra Raiders, Whare made his club debut for the Penrith Panthers at fullback in a 32–10 win at Penrith Stadium. Whare started the season playing at fullback until he cemented a centre position from round 7 onwards. In round 7, against the Parramatta Eels, Whare scored his first try club try for Penrith in the 44–12 win at Penrith Stadium. For the 2013 ANZAC Test, Whare was selected to play for New Zealand at centre in the Kiwis 12–32 loss against Australia. Whare finished the 2013 NRL season with him playing in all of the Panthers 24 matches and scoring 5 tries. Whare was selected in the New Zealand 2013 World Cup squad, playing in 5 matches. He scored 2 tries against Papua New Guinea in the Kiwis 56–10 win. Whare played at centre in the Kiwis 2–34 loss to Australia in the World Cup Final at Old Trafford. On 13 December 2013, Whare agreed to a 3-year contract extension with the Penrith Panthers, until the end of the 2017 season.
Whare played in the 18–16 loss at Penrith Stadium in round 2 against the Canterbury-Bankstown Bulldogs. This was his only match of the season after battling a calf tear injury before a season-ending knee injury happened during training.
Whare made 24 appearances for Penrith in the 2018 NRL season as the club finished 5th on the table and qualified for the finals. Whare played in both finals games as Penrith reached the elimination final against Cronulla-Sutherland but lost 21–20 at the Sydney Football Stadium which ended their season.
2019
Whare made a total of 18 appearances for Penrith in the 2019 NRL season as the club finished a disappointing 10th place and missed out for the finals for the first time since 2015.