Werder Bremen After playing youth football for
Rot-Weiß Erfurt, Gruev moved to
Werder Bremen in 2015. Gruev progressed through Bremen's youth teams, eventually becoming captain of the club's under-19 side before signing his first professional contract with the club in April 2019. He scored the first goal of his senior career in a 4–1 win over
Schalke 04 in April 2022, with a close-range header to put Bremen 1–0 up. Werder Bremen were promoted to the Bundesliga at the end of the season, after finishing 2nd with 63 points. Gruev extended his contract with Werder Bremen in summer 2022.
Leeds United 2023–24 season On 31 August 2023, Gruev signed for
EFL Championship club
Leeds United on a four-year deal for an undisclosed fee. Gruev struggled to break into Leeds' first team in the first half of the season, being limited to just two league starts in 2023, both of which were in a
box-to-box midfielder role rather than as a
deep-lying midfielder, due to the form of
Ethan Ampadu in that role. In his third league start of the season, an injury to centre-back
Pascal Struijk allowed Gruev to be given a start as a deep-lying midfielder in a 3–0 win against
Cardiff City in January 2024 – Gruev was voted man of the match, having completed 68 out of 70 passes, giving him a 97% passing accuracy, a record for a Leeds player (who recorded 50+ passes) since the statistic was first measured in the 2013–14 season. Gruev scored his first and only goal of the season, a free kick in the second leg of Leeds' 4–0
play-off semi-final win against
Norwich City at
Elland Road. However, Leeds were unable to secure promotion back to the Premier League at the first attempt following a defeat to
Southampton in the
play-off final in May 2024.
2024–25 season Having been named in the starting line-ups for most of the season so far, Gruev sustained an injury at Norwich City necessitating surgery to repair meniscus damage in early October 2024. Gruev returned to play as a late substitute in an FA Cup third round home win over
Harrogate Town in January 2025. In May, Gruev won the
2024–25 EFL Championship title with Leeds following a late win over
Plymouth Argyle at
Home Park. Gruev finished the season with two assists, appearing in 23 league matches.
2025–26 season On 6 February 2026, Ilia Gruev recorded his first senior and
Premier League match with two assists in a 3-1 win against
Nottingham Forest at
Elland Road. He became the first player to record two assists in a Premier League match for Leeds United since
Pablo Hernandez in December 2020. ==International career==