Krmar passed all Spartak Subotica youth selections. He signed scholarship contract with club in summer 2013.[3] After the end of his youth career, Milivoj joined the first-team squad, signing a three-year professional contract with club in summer 2016.[4] He made his debut in the 3rd fixture of the 2016–17 Serbian SuperLiga season, against Radnik Surdulica, replacing a captain Vladimir Torbica.[5] In the next fixture, he scored a goal in defeat against Novi Pazar, during the match which he also started as a reserve player.[6] Krmar also scored a goal in a Serbian Cup match against OFK Bačka, played on 20 September 2016.[7] Krmar collected 19 appearances with 2 goals in both domestic competitions.[8] After he started the new season as a back-up player, making an appearance in a match against Borac Čačak,[9] Krmar moved on a half-season loan deal to Bačka 1901 in summer 2017.[10] In February 2018, passing the winter-break with Spartak,[11] Krmar extended a loan deal to Bačka 1901 until the end of season,[12] making 23 appearances in the Serbian League Vojvodina and scoring 9 goals at total.[13]
Hajduk Kula, Radnički Zrenjanin and Timočanin
On 18 January 2019, Hajduk Kula confirmed on their Facebook profile, that they had signed Krmar.[14] In the summer 2019, he left Hajduk Kula and joined Radnički Zrenjanin.[15] He later on played for Timočanin.
Krupa
On 22 July 2020, Krmar signed a three-year contract with Bosnian Premier League club Krupa.[16] He made his official debut for the club in a league match against Borac Banja Luka on 31 August 2020.[17] Krmar terminated his contract with the club on 19 December 2020.[18]