He made his competitive debut for Eskilstuna City on 14 April 2013 in a 7–0 away defeat to IK Sirius, playing all ninety minutes of the match.
In January 2014, Markkula moved to Ykkönen side FC Haka, joining on a one-year contract with an option for a second.
He made his league debut for the club on 12 April 2017 in a 6–2 home victory over RoPS, playing 74 minutes before being replaced by Kevin Mombilo.
[9] He made his first appearance back from his injury on 26 September 2018, coming on as a 64th minute substitute for Tatu Varmanen in a 2–0 home victory over FC Lahti.
[11] Markkula made his first competitive appearance for Finland U21s on 10 October 2011 in a 1–0 defeat to Sweden U21s at the 2011 U21 Euros, coming on as an 83rd minute substitute for Juho Lähde.