Viitorul Constanța Munteanu was born in
Vaslui, Romania. He moved to the
Gheorghe Hagi Academy in
Constanța at age nine, finding the transition difficult and later recalling that he "cried every night" during his first year away from home. His mother eventually relocated to Constanța to support him, helping him adjust and continue his development. Munteanu made his professional debut for
Viitorul Constanța on 27 October 2019, in a 3–2 away
Liga I loss to
Dinamo București. Five days later, he scored his first goal in a 3–0 home success over
Chindia Târgoviște. He amassed three goals from 19 appearances during
his first season as a senior, all in the league championship.
Fiorentina On 26 September 2020, Munteanu was transferred to Italian club
Fiorentina for a rumoured fee of €2 million. During his initial two years with the
Primavera side, he appeared in 40 matches and scored 13 goals. Before moving to Farul, he was close to being loaned to
Rapid București, but the deal fell through because Fiorentina declined to include a permanent transfer clause. On the 28th that month, he scored his first two goals in a 3–1 away victory over defending champions
CFR Cluj. On 6 May 2023, Munteanu netted his second double of the campaign in a 7–2 home thrashing of Rapid București. Fifteen days later, he scored the winner in a 3–2 home success over league contenders
FCSB, securing the national title for Farul with one match remaining. On 28 May, Munteanu ended his spell with ten goals in 29 matches by scoring twice in a 2–1 away victory at CFR Cluj, also missing a
penalty.
Second loan to Farul Constanța On 18 August 2023, Munteanu was sent on another
year-long loan to Farul. He made his debut in
European competitions six days later, coming on for
Adrian Mazilu in a 2–1 home win over
HJK in the
UEFA Europa Conference League play-off round. On 27 August, he scored both goals in a 2–0 home win against
Universitatea Craiova. Munteanu surpassed his previous season's statistics by netting 12 goals in 34 Liga I appearances, and was voted Farul Player of the Year by the fans.
CFR Cluj On 31 July 2024, amid interest from fellow league clubs FCSB and Rapid București, CFR Cluj officially announced the transfer of Munteanu on a four-year contract. CFR Cluj owner Neluțu Varga admitted that the transfer fee was "around" €2 million, contrasting some reports that indicated it might be as high as €2.8 million, and also stated that Fiorentina retained 50% participation rights in a
co-ownership deal. Munteanu registered his debut on 4 August 2024, starting in a 3–2 home Liga I loss to
rivals Universitatea Cluj. One week later, he scored his first two goals in a 3–0 win over
newly-promoted Unirea Slobozia. On 15 September, Munteanu netted another double in a 2–2 home derby draw with FCSB. On 27 January 2025, Louis Munteanu netted his first professional
hat-trick in a 3–1 home victory over his former club Farul Constanța. His consistent goalscoring form continued on 9 March, when he recorded another hat-trick in a 6–0 thrashing of
Gloria Buzău in the final round of the regular season. On 20 April 2025, he scored a brace against FCSB in a 3–2 away defeat in the championship play-offs. On 14 May 2025, Munteanu scored in the Cupa României
final, helping his team secure a 3–2 victory over
Hermannstadt at the
Francisc von Neuman Stadium in
Arad. His final goal of the season, netted in a 1–1 draw with FCSB on 23 May, made him the Liga I top scorer with 23 goals and equalled
Mihai Adam's long-standing club record from the
1973–74 season. CFR Cluj concluded the
campaign as runners-up, and Munteanu was named the Under-21 Player of the Season by
LPF. Munteanu scored his first European goal on 17 July 2025, ten minutes after coming on in a 3–0 home victory over
Paks in the
Europa League first qualifying round. In late August, after returning to Romania following a harsh 2–7 defeat to
BK Häcken in the Conference League
play-off round, he refused to train amid rumours of a transfer abroad and subsequently missed a Liga I match against
Oțelul Galați, which CFR Cluj lost 1–4. By the turn of the year, Munteanu's form declined, as he only managed to score two goals from 14 league matches.
D.C. United On 5 January 2026, Munteanu joined
Major League Soccer team
D.C. United as a
Designated Player, signing a three-and-a-half-year contract with an option for a further year. D.C. United officially announced that it paid a club-record transfer fee of US$7 million (€6 million), with reports also mentioning potential add-ons of up to US$3 million (€2.6 million) and a 35% sell-on clause. ==International career==