Robert Ljubicic

After three full seasons at St. Pölten in the Austrian Bundesliga, it was announced on 8 March 2021 that Ljubičić would join Rapid Wien in the summer of 2021 on a three-year deal. His brother, Dejan, was captain of the club at the time, but his departure to Köln in Germany was announced in April. He made his debut at Rapid in the second qualifying round of the UEFA Champions League against Sparta Prague on 20 July, in his brother's position of central midfield. On 13 June 2022, HNL club Dinamo Zagreb announced the signing of Ljubičić. On 11 October 2022, he scored his first Champions League goal in a 1–1 draw against Red Bull Salzburg.

AEK Athens

On 31 January 2024, Ljubičić joined Super League Greece side AEK Athens for a fee of €4 million, becoming the club's second most expensive acquisition, only behind Orbelín Pineda. He signed a contract running until the summer of 2029. Roughly 20 days later, he scored his first goal in a 3–0 home win against Kifisia.

Loan to LASK

On 22 July 2026, Ljubičić joined Austrian Bundesliga club LASK on loan. A month later, on 25 August, he scored his first goal for the club in a 5–1 victory over Celtic after extra time in the Champions League qualifying play-off round, as the club qualified for the main tournament for the first time in its history.

Ljubičić is of Bosnian Croat descent, so he was eligible to represent Austria, Bosnia and Herzegovina and Croatia. He was capped for the Croatia U20 team in 2019, but decided to switch allegiances to Austria U21 team in 2020. He has not made a senior international debut for either country as of August 2021. In November 2022, Ljubičić opted to represent Croatia instead of Austria.

In Austria, Ljubičić mainly played as a defensive midfielder. However, after joining Dinamo Zagreb, head coach Ante Čačić moved him to the position of left-back. Initially unwanted position, after half a year with Dinamo, Ljubičić stated that he adapted to the position and now prefers it.

His older brother Dejan is also a professional footballer. They were born in Austria to Bosnian Croat parents from Busovača.