Early career

Franks attended Christchurch Boys' High School. His local rugby club is Linwood. He represented New Zealand at Under-21 and Secondary School level.

While at Christchurch Boys' High School, Franks appeared alongside fellow All Blacks Colin Slade and Matt Todd, as well as former Crusaders Nasi Manu and Tim Bateman.^[4]

Provincial

Franks made his debut for Canterbury in the Air New Zealand Cup in 2007. He was also Campbell Johnstone's understudy before he left for France and Franks assumed the tighthead duties for the Canterbury team. His older brother, Ben Franks is also a prop and has played alongside Owen.

Super Rugby

Franks made his debut for the Crusaders in 2009 as a substitute against the Western Force but made his first start in the victory over the Bulls and his stellar performance also secured him an All Black contract. Relatively small in stature, he is known for his great scrummaging technique and mobility around the field. He is also very strong, with the ability to squat 280 kg.

Franks has played over 100 games for the Crusaders since his debut, becoming the 13th Crusader to do so, against the Highlanders in 2015.

Franks started in the Crusaders' historic fixture against the touring British and Irish Lions team on 10 June 2017, playing 50 minutes before being replaced by Michael Ala'alatoa as the Lions beat the Crusaders 12–3. Franks won the 2017 Super Rugby season later in the year, with the Crusaders beating the Lions 25–17 at Ellis Park Stadium in Johannesburg. The Crusaders' win was their eighth title and first since 2008.

Premiership Rugby

On 14 February 2019, Franks travels to England to sign for Northampton Saints in the Premiership Rugby ahead of the 2019–20 season, where he will play alongside his brother Ben Franks at Franklin's Gardens.^[5]

Return to Super Rugby

On 14 May 2021, Franks moves back to New Zealand to join Hurricanes ahead of the 2022 Super Rugby competition. Franks made his Hurricanes debut on the 8th of May 2022 in Wellington against the Fijian Drua.^[6]

2009

His first match for New Zealand came against Italy in 2009, which the All Blacks won 27–6.^[7] Franks was chosen for the 2009 Tri-Nations tournament in New Zealand's first match against Australia. He went on to play the next two games against South Africa before playing once again against Australia. Franks played the penultimate match against South Africa but missed the final match, with Neemia Tialata playing instead. He then came on as a sub against Wales during an international test in November. A week later he started in a win over England and went on to be victorious over France a week later.

2010-2011

Franks became a regular starter for the All Blacks in 2010, supplanting the long-serving Neemia Tialata as New Zealand's first-choice tighthead prop.

His first game was against Ireland with his brother Ben playing with him. They went on to play Wales twice together. He played once again in the Tri-Nations tournament, starting the first four matches against South Africa and Australia. His brother Ben played the third test against South Africa but he missed out. However he appeared in the final match against Australia winning 23–22. He went on to lose the Halloween test against Australia. He took part in four of New Zealand's November friendlies beating England, Scotland, Ireland and Wales.

Franks and his older brother Ben were both selected for the 2011 Rugby World Cup. Franks started in all of the knockout rounds, playing the full 80 minutes of the World Cup final against France on 23 October 2011, with the replacement prop, his brother Ben, not making the field. New Zealand won against France 8–7, with Franks collecting his winners' medal as All Black captain Richie McCaw lifted the trophy, with New Zealand winning the competition for the second time, having won the first Rugby World Cup in 1987. According to the book, Cory Jane Winging It, Random Tales from the Right Wing, by former All Blacks teammate Cory Jane and Scott Stevenson, Franks and brother Ben are said to have celebrated the All Blacks Rugby World Cup 2011 victory by squatting the next day 280 kg for 10 Repetitions.

2012-2015

Franks carried a heavy workload for the All Blacks in 2012, appearing in 13 tests. Franks started 12 times in 2012 with the exception of the third Bledisloe Cup test against Australia on 20 October as he replaced newcomer Charlie Faumuina off the bench as the All Blacks drew against the Wallabies 18-18.

Franks' contribution to the All Blacks in 2013 was not as significant due to injuries, with Charlie Faumuina covering for Franks. The ten tests Franks played in 2013 saw him achieve some personal and professional milestones, playing his 50th test for New Zealand on 14 September 2013 when the All Blacks defeated the Springboks 29–15 at Eden Park. Franks' 50th test was unfortunately overshadowed by the outstanding performance of All Black captain Kieran Read and the ill-discipline of both sides, with Springbok hooker Bismarck du Plessis being red-carded in the 41st minute for elbowing All Black flanker Liam Messam's face. Franks was replaced by Faumuina in the 64th minute of the test.

Franks and his older brother Ben both came off the bench in the second half of New Zealand's final test of 2013, on 24 November that year, with Wyatt Crockett and Charlie Faumuina preferred to start against Ireland for the test. New Zealand was losing 7–22 to Ireland at halftime but Franks lead the forward pack's charge for a comeback, producing one of the best performances of his career, assisting in allowing New Zealand to equalise the score after the 80th minute. Fly-half Aaron Cruden converted Ryan Crotty's 80th minute try, allowing New Zealand to win 24–22, with Franks and his teammates becoming part of the first international rugby team to win every test they played in a calendar year.

After busy seasons in 2014 and 2015, Franks was selected for the 2015 Rugby World Cup and once again started in all three of the knockout rounds for New Zealand. Franks opened the 2015 Rugby World Cup final, against Australia on 31 October 2015, with a huge tackle on Wallabies fullback Israel Folau and played for 54 minutes before being replaced by Charlie Faumuina, who had returned from injury to take part in the tournament. New Zealand beat Australia 34-17 and became the first country to win the Rugby World Cup three times. New Zealand's victory saw Franks and his older brother Ben, who came off the bench to make his final international appearance for New Zealand that day, become the first set of siblings to win a Rugby World Cup multiple times.

2016-2019

Franks had a good season in 2016, starting in all 12 of his test appearances which included a historic 29–40 loss to Ireland on 5 November 2016.

Prior to being selected for New Zealand's three-test series against the British and Irish Lions and Pasifika Challenge against Samoa, Franks' achilles' tendon was observed to be in noticeable pain. Franks still managed to play in five tests for the All Blacks in 2017, including the Lions series, before being ruled out of the second Bledisloe Cup test of the year against Australia due to tearing his achilles' tendon at training. Franks was immediately replaced on the match-day sheet by former Crusaders team-mate Nepo Laulala who had not played for the All Blacks since 2015 due to his own run of injury. Laulala started in all of the remaining tests in 2017 in Franks' absence.

Franks was re-selected for New Zealand in 2018 for the three-test series against France for the June internationals, having recovered from injury during the 2018 Super Rugby season. Franks started in all three tests against France despite his lack of game-time in 2018, and performed to a reasonable level, with Ofa Tu'ungafasi replacing Franks off the bench in all three tests. The All Blacks won the series 3–0.

After finishing Super Rugby, with a title win, Franks played his 100th test for New Zealand, on 25 August 2018. Franks started for his 100th test, which was against Australia at Eden Park. Franks became the first rugby player in history to reach 100 tests without scoring any points in his career, but performed well before being replaced by Ofa Tu'ungafasi in the 52nd minute. The All Blacks won Franks' 100th test, beating Australia by 40–12, winning the Bledisloe Cup once more. Franks went on to play 6 more tests during the 2018 season, including the 9–16 loss to Ireland, with Nepo Laulala establishing himself as Franks' deputy throughout the season.

Coming off the back of an injury-plagued Super Rugby season, Franks played two tests in his final season in New Zealand, taking part in the 2019 Rugby Championship for the tenth time. After a poor performance against Australia, in a record 26–47 defeat, Franks was axed from the match-day 23 for the second Bledisloe Cup test. On 28 August 2019, Franks was dropped from the All Blacks, missing out on the 31-man squad for the 2019 Rugby World Cup, with Nepo Laulala, Atu Moli, Joe Moody, Angus Ta'avao, and Ofa Tu'ungafasi being the preferred props.^[8][9] Having signed for Northampton earlier in 2019, Franks’ shock omission from the squad effectively ended his decorated international career.