Born in
Groningen, Markelo was signed by English club
Everton in 2017 after being scouted playing in a youth tournament for
FC Volendam. He moved on loan to
FC Twente in July 2020. He signed for
Jong PSV in August 2021 on a permanent deal. On 9 July 2022, Markelo joined
Excelsior on a three-year contract. At the end of the 2022–23 season, his contract with Excelsior was terminated by mutual consent. On 3 August 2023, Markelo signed a contract with
Fortuna Sittard for one season, with an option to extend for two more years. After one season at Fortuna, Markelo joined
Eerste Divisie club
Roda JC on 27 June 2024. He signed a two-year deal, with an option to extend for one more year. He made his competitive debut for the club on 4 October, replacing
Jay Kruiver in the 80th minute of a 3–0 victory against
Excelsior. The contract with Roda was mutually dissolved on 22 January 2025. Later that month, Markelo signed for
Bulgarian First League club
Hebar Pazardzhik. In September 2025, Markelo joined
Eerste Divisie side
Vitesse. ==International career==