Poljičak made his ATP main draw debut at the
2021 Croatia Open Umag after receiving a wildcard into the doubles main draw. Partnering with
Admir Kalender, the pair defeated second seeds
Pablo Cuevas and
Fabrice Martin in the first round in straight sets but lost in the next round to eventual champions
Fernando Romboli and
David Vega Hernández in three sets. At the
2022 Zagreb Open he reached his maiden Challenger final as a wildcard where he lost to
Filip Misolic. At the same tournament also as a wildcard he reached the semifinals in doubles partnering
Antonio Šančić. As a result he reached the top 550 at World No. 549 (up 923 positions) in the singles rankings and the top 375 in doubles (up 88 positions) on 16 May 2022. he received a wildcard for the qualifying draw of the
2023 Wimbledon Championships to make his Grand Slam qualifying debut. He reached a new career high ranking of No. 409 on 26 August 2024, following back-to-back ITF titles in Maribor on clay. ==ATP Challenger Tour finals==