Foran previously played for the Manly-Warringah Sea Eagles, Canterbury-Bankstown Bulldogs, Parramatta Eels and the New Zealand Warriors in the National Rugby League.

[8] Foran played in the North Sydney Bears Harold Matthews Cup and SG Ball teams before being signed by the Manly club.

[12] Foran became Sea Eagle number 526 when he made his first grade debut in round 15 against the Canberra Raiders, starting at five-eighth and scoring a try in Manly's 20–14 win at Brookvale Oval.

[16] On 7 November 2009, Foran become Kiwi number 757 when he made his test debut, playing in the centres in New Zealand's 12–20 loss to England at Alfred McAlpine Stadium.

[19] After a strong start to the season, Foran was rewarded with selection as halfback for New Zealand in the 2010 Anzac Test, which was played at Melbourne's new AAMI Park.

Following the early rounds of the 2011 NRL season, Foran was rewarded with selection at halfback inside of Benji Marshall at five-eighth for the annual Anzac test match against Australia at the Gold Coast's Cbus Super Stadium.

[24] But soon after, Thurston suffered a knee injury in the third State of Origin game and during his absence Foran produced some man-of-the-match awards to seemingly catch up.

[citation needed] Foran was suspended following his role in the brawl against Melbourne in round 25 in Manly's 18–4 win at Brookvale Oval, ruling him ineligible for that year's medal.

[citation needed] On 2 October 2011, Foran played five-eighth in the Sea Eagles' 24–10 win over the New Zealand Warriors in the grand final in front of 81,988 at the ANZ Stadium in Sydney.

After the 2011 grand final victory, Foran was selected in the New Zealand Kiwis' squad for the trans-Tasman test game against Australia and the 2011 Four Nations tournament.

For his part, Foran admitted after re-signing with Manly that he had dinner with Hasler and his family to personally inform his old coach and mentor of his decision to stay with the reigning NRL premiers.

[35] During week 2 of the 2012 NRL Finals Series in which Manly played the North Queensland Cowboys, Foran was involved in a try scored by Michael Oldfield.

After a Daly Cherry-Evans bomb in the 62nd minute, some, including Cowboys five-eighth and captain Johnathan Thurston, claimed that Foran had knocked the ball forward, which ultimately led to a try being awarded by video referees Steve Clark and Paul Simpkins as 'benefit of the doubt'.

[36] Thurston was later quoted as telling referee Shayne Hayne that, "(the Cowboys) had been robbed twice," the first time being the 52nd minute try to Jorge Taufua.

[39] In round 1, Foran started the 2013 NRL season with a man-of-the-match strong performance in Manly's 22–14 win over the Brisbane Broncos at Suncorp Stadium.

[44] Coach Stephen Kearney had originally planned to rest Foran, along with the Sydney Roosters' players, for the team's World Cup warm-up game against the Cook Islands as they had all played in the NRL Grand Final.

[52][53] Following the World Cup, Foran won the Steve Watene Memorial medal on 9 December 2013, becoming only the second recipient after Jeremy Smith to win this award.

[58][59] On 25 October 2014, Foran played his first Kiwi-test match at five-eighth in the Four Nations tournament round 1 opener at Suncorp Stadium, Foran produced a strong performance; as he, along with his halves-partner Shaun Johnson, guided the Kiwis to a 30–12 win over Australia, as well as guiding the team to their first win over Australia since the 2010 Four Nations final.

[68][69][70] On 15 November, Foran played at five-eighth in the Four Nations tournament's grand final clash against Australia at Wellington's Westpac Stadium, producing a strong performance making 22 tackles, 6 runs for 60 metres, 1 line-break, 2 line-break assists, 2 off-loads, 1 try-assist (to Manu Vatuvei in the second half of the game) and 2 try-saving tackles.

[84] After Foran missed the season opening match due to injury,[85] he made his club debut for the Eels in round 2 against the North Queensland Cowboys, where he played at halfback in the 20–16 win at Parramatta Stadium.

[88] On 28 April 2016, Foran was rushed to hospital in an ambulance after he overdosed on prescription medication and he was subsequently granted indefinite leave.

[95] On 28 June 2016, Foran was stripped of his captaincy and fined $5,000 for unprofessional conduct by the Eels after he did not turn up to a rehabilitation session and drank alcohol while being injured.

[100] First, Foran lead a pass to Simon Mannering to score, then he proved the difference with a clutch play down a short-side, breaking tackles and putting Muamalo in for the crucial try.

On 10 May 2017,[101] the Canterbury-Bankstown Bulldogs signed New Zealand five-eighth Kieran Foran on a three-year deal that would keep him at Belmore until the end of the 2020 NRL season.

In round 1 of the 2018 NRL season, he made his club debut for the Canterbury-Bankstown Bulldogs against Melbourne Storm, start at five eighth 36–18 loss at Perth Stadium.

Canterbury released a statement saying "Bulldogs playmaker Kieran Foran is to undergo surgery for a high ankle sprain, meaning he is likely to miss 10 to 12 weeks".

[105][106] In February, it was revealed that Foran would miss the majority of the 2020 NRL season with a shoulder injury,[107] however, he was able to recover in time for round 4 of the competition after the extended break due to COVID-19.

In round 17, Foran scored a try but was later taken from the field after suffering a torn pectoral injury in Canterbury's 18–14 loss to the Gold Coast at ANZ Stadium which left the club bottom of the table.

[110] In Round 17, Foran was named the teams’ captain, the 65th in the club's history, due to the absence of Daly Cherry-Evans, who was in preparations for his State of Origin series duties.

Foran played 25 games for Manly in the 2021 NRL season including the club's preliminary final loss against South Sydney.