Having originally signed for the club as an Under-15, Jakubiak joined the club on a scholarship in May 2012. While in the academy, Jakubiak's strike against Peterborough United academy side earned him a nomination for January's League Football Education Goal of the Month award and ended up taking the award.
Jakubiak had appeared as an unused substitute in games against Derby County and Charlton Athletic, but made his debut from the start in Watford's defeat at home to Huddersfield Town on 3 May 2014 – the final game of the season. Six days after making his Watford debut, Jakubiak signed his first professional contract on 9 May 2014, signing a two-year deal with Watford, with the club having a further option on an additional year. After the 2014–15 season came to an end, Jakubiak signed a contract with the club, keeping him at Vicarage Road until 2017.
After impressing in Watford's Under-18 side, Jakubiak was loaned to Conference side Braintree Town on 1 January 2014. His Watford team-mate Bernard Mensah joined him at Cressing Road shortly afterward. In total, Jakubiak made 11 appearances during his loan spell, including two starts, and scored one goal against Wrexham.
On 13 August 2014, Jakubiak moved on loan to League Two side Oxford United until 4 January 2015. He made his debut as a substitute in a 2–1 defeat to Mansfield Town on 16 August 2014. Jakubiak scored his first Oxford United goal, on his first start, in their game against Dagenham & Redbridge on 30 August 2014. After three months at the club, he was recalled by Watford on 4 November.
On 27 November 2014, he joined League Two side Dagenham & Redbridge on a one-month-long youth loan. Jakubiak scored on his debut the next day, on 28 November 2014, in a 2–0 win over Bury. Following his debut, Jakubiak hopes he can get as much playing time at the club. Jakubiak's loan spell with the club was extended on 31 January 2015. The day Jakubiak's loan spell expired, Jakubiak scored his second goal for Dagenham & Redbridge, in a 3–1 win over Cheltenham Town. After that, Jakubiak's loan spell with the club was extended further until the end of the season, which he was happy with the decision. Jakubiak then scored his third goal of the season, in a 3–1 loss against Burton Albion on 21 February 2015 and two months later on 18 April 2015, Jakubiak scored, in a 3–2 win over Newport County. Jakubiak made 23 appearances and scored four times for the club.
On 31 August 2016, Jakubiak joined Fleetwood Town on loan until January of the 2016–2017 season. He scored his first goal for Fleetwood in an EFL Trophy tie against Carlisle United on 9 November 2016. Although he originally joined for the duration of the season, he was recalled by Watford after an injury crisis at the club.
On 30 January 2017, Jakubiak joined Wycombe Wanderers on loan until the end of the 2016–17 season.
Despite being born in Westminster, England, Jakubiak was monitored by Scotland national football team's John Collins, over his eligibility to play for Scotland or Poland, due to his Polish ancestry.
On 22 August 2014, Jakubiak was called by the Scotland U19 squad. Jakubiak made his Scotland U19 debut, where he came on as a substitute for Harry Cardwell in the 56th minutes, in a 2–2 draw against Czech Republic U19.As of match played 14 April 2017.