On 25 February 2012, Gutherson re-signed with the Manly Warringah Sea Eagles on a 2-year contract. In 2012 and 2013, he played for the Sea Eagles' NYC team. In August 2012, he played for the Australian Schoolboys.
2013
On 20 April, he played for the New South Wales under-20s team against the Queensland under-20s team. In Round 26 of the 2013 NRL season, he made his NRL debut for the Sea Eagles against the Penrith Panthers, scoring a try on debut.
2014
On 3 May, Gutherson again played for the New South Wales Under-20s team against the Queensland Under-20s team. On 9 July, he played for the New South Wales Residents against the Queensland Residents. His season suffered a setback when he broke a bone in his right foot during Sea Eagles' 40-8 win over the Wests Tigers at Brookvale Oval in Round 18. He made his return to the side as a late replacement for regular fullback Brett Stewart in Round 26, though with Stewart's return, he was overlooked for the NRL Finals series. He finished off the 2014 season having played in 3 games for the Sea Eagles, scoring a try in each game. On 21 September, he was named as the 18th-man reserve in the 2014 New South Wales CupTeam of the Year. On 18 October 2014, he played for the Junior Kangaroos against the Junior Kiwis.
2015
A shoulder injury to international centre Steve Matai saw Gutherson selected in the centres for the Sea Eagles' opening game of the 2015 NRL season against the Parramatta Eels at Parramatta Stadium. He only lasted 13 minutes and 37 seconds of the game before he ruptured the Anterior cruciate ligament in his right knee. Later scans confirmed the anterior cruciate ligamentknee injury and he was ruled out for the remainder of the season. On 28 April, he re-signed with the Sea Eagles on a 2-year contract. However, on 27 September, he was released from the final 2 years of his contract, making him a free agent for 2016, due to salary cap pressure at the Sea Eagles. On 3 November, he signed a 2-year contract with the Parramatta Eels starting in 2016.
2016
Gutherson represented City Origin in 2016, playing at fullback in their 44-30 win over Country Origin. On 20 December, it was announced that the Eels had re-signed Gutherson to a 3-year contract that will see him at the club until the end of 2019.
2017
2017 would prove to be Gutherson's best year yet as he put in a number of good performances throughout the season while switching between Fullback, Centre, and the halves. Some notable performances include scoring 2 tries in a 26-6 victory over North Queensland, scoring a double against St George in a 24-10 victory. In Round 20 Gutherson scored a try plus setting up another in Parramatta's 17-16 victory over Wests Tigers. This match would prove to be Gutherson's last of the season as he was taken off the field with an injury which was later to be revealed as a season ending ACL knee injury Despite an abrupt end to the season, Gutherson won the Provan-Summons Medal for people's favourite NRL player in 2017.
2018
After the ACL knee injury, Gutherson returned first grade in round 7, played at fullback against his old club Manly, scoring a try. In round 8 against the West Tigers, he played his 50th NRL game in the Eels' 24-22 win. On 11 May, Parramatta were leading arch rivals Canterbury 12-8 going into the second half. Towards the end of the game, Canterbury put through a grubber kick and Gutherson tried to kick the ball out of play but missed completely and Canterbury scored a try. Canterbury went on to win the game and Gutherson made a public apology to the fans in the aftermath, saying "It's shattering, You work so hard and it comes down to that play and I didn't make it. I take the loss on me. As a player, that's what you do. There were tears in the sheds. It's heartbreaking. You put everything into the game and you come out with nothing. We're bottom of the table.". Gutherson ended 2018 with 19 appearances for Parramatta shifting between Fullback, Centre and Five-Eighth as the club endured a horror year on and off the field finishing last on the table and claiming its 14th wooden spoon. Gutherson was also made a co captain of the club in 2018. With the Eels without any obvious leaders, due to his reported admirable leadership qualities and excellent attitude when training Gutherson was made the on field captain with Tim Mannah handling media duties.
2019
At the start of the 2019 season, Gutherson was named captain of the Parramatta side and the first choice fullback ahead of Bevan French. In Round 2, Gutherson scored 2 tries as Parramatta defeated arch rivals Canterbury 36-16. On 16 May 2019, Gutherson re-signed with Parramatta until the end of the 2022 season. Gutherson made a total of 26 appearances for Parramatta in the 2019 NRL season as the club finished 5th on the table and qualified for the finals. Gutherson played in both finals game for Parramatta as they defeated Brisbane 58-0 in week one of the finals. The following week, Parramatta were defeated by Melbourne 32-0 at AAMI Park in the elimination semi final. On 30 September, Gutherson was named in the Australia PM XIII side at Fullback. On 7 October, Gutherson was named in the Australian side for the 2019 Rugby League World Cup 9s.
2020
In round 7 of the 2020 NRL season, Gutherson kicked his first career field goal as Parramatta defeated Canberra 25-24 in golden point extra-time at Bankwest Stadium.
