He played his junior football for the Wellington Cowboys and Cronulla-Caringbah Sharks, before being signed by the Cronulla-Sutherland Sharks. Peachey played for the Sharks' NYC team in 2010 and 2011. At the end of 2011, Peachey was named at in the 2011 NYC Team of the Year. In 2012, Peachey graduated into the Sharks NSW Cup team.
2013
In Round 10 of the 2013 NRL season, Peachey made his NRL debut for the Cronulla-Sutherland Sharks against the Canberra Raiders, playing off the interchange bench in the 30-20 win against the Canberra Raiders at Shark Park. On 17 June 2013, Peachey signed a 2-year deal with the Penrith Panthers from the 2014 season. In Round 26 against the Canberra Raiders, Peachey scored his first NRL career try in his last match for the Sharks in the 38-18 win at Canberra Stadium. Peachey finished his debut year in the NRL with him playing in 7 matches and scoring 1 try for the Sharks in the 2013 NRL season. On 22 September 2013, Peachey was named at lock in the 2013 New South Wales Cup team of the year. On 6 October 2013, Peachey played in the NSW Cup Grand Final against the Windsor Wolves, playing at lock and scoring a try in the 36-8 win.
2014
In February, Peachey was selected in the Panthers inaugural Auckland Nines squad. In Round 1, he made his club debut for the Panthers against the Newcastle Knights, playing off the interchange bench in the 30-8 win at Penrith Stadium. In Round 12, against the Parramatta Eels, he scored his first and second tries for the Panthers in the 38-12 win at Penrith Stadium. Peachey's strong start to the season finished in Round 18 after he suffered a pectoral-tear injury. Peachey finished off his debut year with the Panthers with him playing in 14 matches and scoring 3 tries in 2014 NRL season.
2015
On 13 February, Peachey played at second-row for the Indigenous All Stars against the NRL All Stars in the 2015 All Stars match at Cbus Super Stadium, the Indigenous side winning 20-6. On 3 May, he played for New South Wales City against New South Wales Country, playing at lock in City's 22-34 loss at Wagga Wagga. He finished off the 2015 season having played in 22 matches and scoring 5 tries for the Panthers. On 26 September, he played for the Prime Minister's XIII against Papua New Guinea, playing off the interchange bench in his team's 40-12 win in Port Moresby. On 15 December, he was named on the interchange bench for the Indigenous All Stars team to play against the World All Stars on 13 February 2016.
2016
On 13 February, Peachey again played for the Indigenous All Stars against the new World All Stars in the 2016 All Stars match, playing off the interchange bench in the 12-8 loss at Suncorp Stadium. On 8 May, he played for City Origin against Country Origin, where he started at lock in the 44-30 win in Tamworth. In round 10, against the New Zealand Warriors, he scored a hat-trick of tries in the 30-18 win at AMI Stadium. In the next match, in Round 11 against the Gold Coast Titans, with scores at 24-all, Peachey went from hero to zero after he dropped a pass from Peter Wallace and didn’t dive on the ball. Titans halfback Ashley Taylor picked up the ball and raced downfield before Anthony Don acrobatically dived over in the corner one play later to seal a bizarre 28-24 win at Penrith Stadium. In July 2016, Peachey was axed from the Panthers squad for their Round 18 clash with the Cronulla-Sutherland Sharks after he returned training late after a night out in Cronulla. Peachey had planned to head back to Penrith in the morning but slept in and attempted to make it to training on time by catching a taxi with the trip costing him $250 and arriving in the clothes he was wearing the night before with no training gear. He eventually played in the Panthers NSW Cup team for the week. Peachey returned in the next match, playing at centre and scoring a try in the 22-18 win. After Peta Hiku and Dean Whare suffered season ending knee injuries at the start of the season, Peachey was shifted from being a bench utility to centre. Peachey finished the 2016 NRL season with him playing in 24 matches and scoring 13 tries for the Panthers.
2017
On 10 February 2017, Peachey played for the Indigenous All Stars against the World All Stars in the 2017 All Stars match, playing off the interchange bench in the 34-8 win at Hunter Stadium. On 7 May 2017, Peachey again played for City Origin in the last ever City vs Country Origin fixture, playing at centre in the 20-10 win in Mudgee. In the Panthers Week 1 Elimination Final match against the Manly-Warringah Sea Eagles at Sydney Football Stadium, Peachey scored a controversial try when the scores where locked at 10-10 all in the 73rd minute. The ball appeared to bounce off Peachey’s arm into his hand from a rebound off a grubber kick from team mate Bryce Cartwright, dived over the try line which was given the green light by the video referee bunker and the Panthers would be 22-10 winners and advance into Week 2 of the finals series. Peachey finished the 2017 NRL season with him playing in 25 matches and scoring 8 tries for the Panthers.
2018
On 2 March 2018, Peachey announced that he signed a 3-year deal with the Gold Coast Titans worth $1.5 million, starting from 2019. In round 8 of the 2018 NRL season against the Canterbury-Bankstown Bulldogs, Peachey played his 100th NRL game in Penrith's 22-14 win at Penrith Stadium.
2019
Peachey made a total of 21 appearances for the Gold Coast in the 2019 NRL season as the club endured a horror year on and off the field. During the halfway mark of the season, head coach Garth Brennan was sacked by the club after a string of poor results. The Gold Coast managed to win only 4 games for the entire season and finished last claiming the Wooden Spoon.
