Marselino started his senior career with Persebaya Surabaya in 2021, emerging through its youth system. During his first season he became a regular starter and won the Liga 1Best Young Player Award and was named of as one of the 60 most talented and promising players by The Guardian in the same year.[4] He joined Belgian side Deinze in February 2023.[5]
Marselino has represented Indonesia at various youth level, finishing third at the 2019 AFF U-15 Championship and winning bronze medal at the 2021 Southeast Asian Games.[citation needed] He made his senior international debut in 2022, becoming the second youngest Indonesian debutants and scored his first goal at the 2023 AFC Asian Cup qualifiers becoming the nation's youngest goalscorer.
Marselino broke into the senior team of Persebaya Surabaya in the 2021–22 Liga 1 season a few days after his 17th birthday following two years in its youth system. He debuted in a 12 September 2021 Liga 1 match against Persikabo 1973 that ended with a 3–1 victory for Persebaya.[6][7] On 6 November 2021, he scored his first league goal and saved his team from defeat in a 2–2 draw with rival Arema.[8] On 4 December 2021, he scored the opening goal in the first half and give his first assists to Taisei Marukawa in Persebaya's 2–0 win over Barito PuteraatManahan Stadium.[9]
On 5 January 2022, Marselino give another assists to Samsul Arif in early of first half, and scoring in second half in Persebaya's 3–1 win over Bali United.[10] nine days laters, he was involved in Persebaya's 2–1 win over PSM Makassar, scoring in the 55th minute.[11] On 23 August, Marselino scored the decisive goal before match ended in a 1–0 home win against PSIS Semarang at the Gelora Bung Tomo Stadium, he was also selected as 'Man of the Match' in that match.[12][13]
On 18 January 2023, Marselino scored a brace for the club in a 0–5 away win against Persita Tangerang.[14]
On 1 February 2023, Marselino officially joined Belgian First Division B club, Deinze with a one and a half year contract.[15] Marselino made his debut with Deinze against Jong Genk on 25 February, where he got subbed on in the 80th minute replacing Jellert Van Landschoot.[16]
Marselino scored his first league goal for Deinze on 22 April 2023 against Virton in a 3–1 win.[17]
Marselino started to represent Indonesia from the age of 14 when he debuted in a Indonesia U-17 team match against Vietnam U-17 in the 2019 AFF U-15 Championship.[18] He scored his first international goal in that debut that ended with a 2–0 win.[19]
Marselino was part of the Indonesia U-23 team that won bronze in the 2021 Southeast Asian Games. He scored two goals in the six matches that he played in that tournament.[22] He was again called up for the under-23 national team for the 2023 Southeast Asian Games, in which he scored two goals in the tournament and helped the team won the gold medal for the first time in 32 years.[23]
In January 2022, Marselino crossed a milestone when he was called up to the Indonesia national team for two friendly matches against Timor-LesteinBali.[26] He earned his first senior cap on 27 January 2022 in the first match that ended with a 4–1 win for Indonesia.[27] He became the second-youngest Indonesian to play for the main national team at the age of 17 years 4 months and 18 days, just behind Ronaldo Kwateh who debuted in the same match.[27]
On 14 June 2022, Marselino became the youngest goal-scorer in the Indonesia senior team at the age of 17 years and 9 months, after scoring against Nepal in the 2023 AFC Asian Cup qualification in a 7–0 win.[28]
Marselino was called up for his first AFF Championship tournament by Shin Tae-yong.[29] he scored a goal against Philippines in the 2022 AFF Championship group stage, not only that, the goal went viral on social media and caught the attention of the Brazilian's, Richarlison because of his similar goal celebration.[30] He was also awarded the Young Player of the Tournament award.[31]
On 15 January 2024, Marselino scored the equalizing goal against Iraq in an eventual 1–3 losing effort in the 2023 AFC Asian Cup group stage.[32] He became the youngest goalscorer in the tournament and the nation’s all time in the AFC Asian Cup.
His traditional name based on the Ngada people's customs is Marselino Ferdinan Dhewa Kedhi. Marselino's mother comes from Surabaya, while his father comes from Ngada, East Nusa Tenggara. He spent his school years in Surabaya.[33]
Marselino is the youngest child of four siblings. During the 2021–22 Liga 1 season, Oktafianus Fernando, his older brother, played for Persebaya Surabaya before Oktafianus left for PSIS Semarang in the following season.[34]