Junior Eldstal

When he turned 19, he was enrolled in UWE Hartpury College Football Academy, where he studied a Sports Coaching degree while also being a part of the elite football programme. During his time with UWE, he also played for Slimbridge in 2012 on a part-time basis in the Hellenic Football League before he decided to play for Sarawak in the Malaysia Premier League.

In April 2013, Eldstål signed with Sarawak FA and made his league debut on 17 April 2013 in a second leg FA Cup Malaysia 0–2 home defeat against Kelantan FA as a last minute substitution. Since Eldstål joined the Crocs in April, he helped Sarawak FA win their first premiership domestic trophy in almost 16 years. Sarawak had an unbeaten run which was the league record. Eldstål, who had yet to score his first goal for Sarawak, had the distinction of providing two assists leading to two goals as the other goal scored by Zamri Morshidi was a similar result provided by his back-flick again. Sarawak officially booked their spot in the quarterfinals of the 2013 Malaysia Cup as they smashed in six goals against Perak to secure an impeccable 6–1 win.

In July 2013, Eldstål was called up to join the Harimau Muda A squad for the World University Games in Kazan, but due to some technical issues he was not allowed to be registered for the tournament. On 11 July 2013, Eldstål was named in the senior squad for the first time in K. Rajagopal 23-man shortlist for the upcoming July friendly against Chonburi FC on 16 July 2013. He later received a call-up for a match against Chelsea and Barcelona.

On 7 September 2013, Eldstål earned his first under-23 cap in a game against Singapore U-23 and scored his first goal for the squad on 14 September 2013 in the Merdeka Cup final against Myanmar U-23 and Malaysia emerged as Asia Cup Champion after defeating Myanmar 2–0 at the Darul Makmur Stadium, which concluded with his goal in the 90th minute.

Eldstål is half-Swedish and half-Malaysian. He received the FAM Most Promising Player Award in 2013.

In 2014, Sarawak was back in the Malaysia Super League since 2012, Eldstål was awarded a new, improved contract for his progress that would keep him at Sarawak FA until the end of 2014 season, but his debut for the league was delayed after suffering a back injury setback on 14 September 2013, followed by his operation in November then a two month program of rehabilitation. His first full start of the season started in March and assisted a good few goals for Suppiah Chanturu and Ryan Griffiths. On 15 April, he produced a display with influential in scoring a goal to a 3–2 win at home over ATM FA. Eldstål subsequently ended 2013–14 season with 55 appearances in all.

On 11 November 2014, Eldstål announced that he had signed a contract with one of the top teams in Southeast Asia, Johor Darul Ta'zim FC under coach Bojan, playing in the Malaysia Super League, until 2015. On his move, he was promptly inserted into the starting eleven playing as a centre back for the first pre-season matches against Johor Darul Ta'zim II, PKNS and Penang FA.

In September 2014, Ong Kim Swee named Eldstål in his final 23-man squad for the 2014 Asian Games, playing in Group A for the tournament in Incheon, South Korea. Eldstål played just two games in the tournament, a 0–3 loss in the first round match against the host South Korea. He missed the second round match, a 4–0 win over Laos, due to a minor calf injury. With only playing two games during the tournament, Malaysia finished third in the group after being knocked out as they lost 0–3 to Saudi Arabia on 21 September.

On 14 March, JDT fell behind to a 35th-minute goal by Sime Darby to trail 0–1 at halftime. Eldstål was then played in midfield again alongside Hariss Harun and regular defender Marcos António, where Junior scored his first-ever Super League goal of this season in the 61st-minute equaliser in a 1–1 away game over Sime Darby. He scored his second goal for the club on 24 April 2015 in the 2–1 defeat for Perak.

On 29 October 2018, Eldstål uploaded a video and a statement to his personal social media, confirming his end of stay in Johor Darul Ta'zim and return to UK.

On 5 March 2019, Eldstål debuted for English non-league side Metropolitan Police F.C. in a 2-1 win over Kings Langley F.C., Eldstål's inclusion in the team was not announced publicly prior to the fixture and was formally announced by the club a couple of days later, confirming Eldstål had signed until the end of the 2018/19 season.