He joined RB Leipzig on 31 August 2015, signing on a four–year contract for an undisclosed fee (it was reported to have cost three million euros).
However, his move to RB Leipzig caused outrage among FC St. Pauli supporters.

Halstenberg made his RB Leipzig debut, starting the whole game, in a 2–0 win over Paderborn 07 on 11 September 2015.
In a follow–up match, he scored his first goal for the club, in a 1–1 draw against 1.
FC Heidenheim.
Since joining the club, he became a first team regular for the side and found himself in a competition in the left–back position with Anthony Jung.
Halstenberg then scored his second goal of the season, in a 2–1 win over SV Sandhausen on 1 November 2015.
He later set up two goals, setting up the first goal and the third goal, in a 4–2 win over MSV Duisburg on 6 December 2015.
Despite being sidelined later in the 2015–16 season, Halstenberg remain featured in the first team, as he played nearly every minute of Leipzig's successful campaign in the 2.
Bundesliga, and as a left-back, was instrumental in Leipzig's league-leading defense.
In his first season at RB Leipzig, Halstenberg made twenty–five appearances and scoring two times in all competitions.

In the 2016–17 season, Halstenberg made his Bundesliga debut, starting the whole game, in a 2–2 draw against TSG 1899 Hoffenheim in the opening game of the season.
He continued to remain a first team regular, playing in the left–back position.
 His performance soon earned himself praised by the German media.
After suffering from an injury in December, he returned to the starting lineup against Eintracht Frankfurt on 21 January 2017, setting up two goals: the first goal and the third goal, in a 3–0 win.
Halstenberg started in every matches since the start of the season until he was sidelined with injury in early–April.
He returned to the starting line-up, playing in the left–back position, in a 4–0 win over SC Freiburg on 15 April 2017.
After returning from injury, he missed the last three matches of the season, due to substitute bench.
At the end of the 2016–17 season, Halstenberg went on to make thirty–one appearances in all competitions.

In the 2017–18 season, Halstenberg continued to remain a first team regular, playing in the left–back position at the start of the season.
Halstenberg set up a goal, setting up the first one, in a 4–1 win over SC Freiburg on 27 August 2017.
He made his UEFA Champions League debut, starting the whole game, in a 1–1 draw against AS Monaco on 13 September 2017.
It wasn't until on 12 December 2017 when Halstenberg scored his first goal of the season, in a 1–1 draw against VfL Wolfsburg.
This was followed up by scoring his second goal of the season, in a 3–2 loss against Hertha BSC.
However, Halstenberg was later plagued with injuries and eventually sidelined for the rest of the 2017–18 season.
While on the sidelined, he signed a contract extension with the club, keeping him until 2022.
At the end of the 2017–18 season, Halstenberg went on to make twenty–three appearances and scoring two times in all competitions.

At the start of the 2018–19 season, Halstenberg was sidelined with injuries, as he returned to training in July.
It wasn't until on 23 September 2018 when he made his first appearance of the season, coming on as a late substitute, in a 1–1 draw against Eintracht Frankfurt.
Since returning to the first team, Halstenberg regained his first team place, playing in the left–back position.
In addition to playing in the left–back position, he also plays in the left–midfield position in a number of matches.
It wasn't until on 1 February 2019 when Halstenberg scored his first goal of the season, as well as, setting up the second goal, in a 3–1 win over Hannover 96.
In the quarter–finals of DFB-Pokal, he scored his second goal of the season, in a 2–1 win over FC Augsburg on 2 April 2019.
Eighteen days later, on 20 April 2019, Halstenberg scored twice for the side, in a 2–1 win over Borussia Mönchengladbach.
He started the whole game in the final against Bayern Munich, as RB Leipzig lost 3–0.
At the end of the 2
He joined RB Leipzig on 31 August 2015, signing on a four–year contract for an undisclosed fee (it was reported to have cost three million euros). However, his move to RB Leipzig caused outrage among FC St. Pauli supporters.
Halstenberg made his RB Leipzig debut, starting the whole game, in a 2–0 win over Paderborn 07 on 11 September 2015. In a follow–up match, he scored his first goal for the club, in a 1–1 draw against 1. FC Heidenheim. Since joining the club, he became a first team regular for the side and found himself in a competition in the left–back position with Anthony Jung. Halstenberg then scored his second goal of the season, in a 2–1 win over SV Sandhausen on 1 November 2015. He later set up two goals, setting up the first goal and the third goal, in a 4–2 win over MSV Duisburg on 6 December 2015. Despite being sidelined later in the 2015–16 season, Halstenberg remain featured in the first team, as he played nearly every minute of Leipzig's successful campaign in the 2. Bundesliga, and as a left-back, was instrumental in Leipzig's league-leading defense. In his first season at RB Leipzig, Halstenberg made twenty–five appearances and scoring two times in all competitions.
In the 2016–17 season, Halstenberg made his Bundesliga debut, starting the whole game, in a 2–2 draw against TSG 1899 Hoffenheim in the opening game of the season. He continued to remain a first team regular, playing in the left–back position.  His performance soon earned himself praised by the German media. After suffering from an injury in December, he returned to the starting lineup against Eintracht Frankfurt on 21 January 2017, setting up two goals: the first goal and the third goal, in a 3–0 win. Halstenberg started in every matches since the start of the season until he was sidelined with injury in early–April. He returned to the starting line-up, playing in the left–back position, in a 4–0 win over SC Freiburg on 15 April 2017. After returning from injury, he missed the last three matches of the season, due to substitute bench. At the end of the 2016–17 season, Halstenberg went on to make thirty–one appearances in all competitions.
In the 2017–18 season, Halstenberg continued to remain a first team regular, playing in the left–back position at the start of the season. Halstenberg set up a goal, setting up the first one, in a 4–1 win over SC Freiburg on 27 August 2017. He made his UEFA Champions League debut, starting the whole game, in a 1–1 draw against AS Monaco on 13 September 2017. It wasn't until on 12 December 2017 when Halstenberg scored his first goal of the season, in a 1–1 draw against VfL Wolfsburg. This was followed up by scoring his second goal of the season, in a 3–2 loss against Hertha BSC. However, Halstenberg was later plagued with injuries and eventually sidelined for the rest of the 2017–18 season. While on the sidelined, he signed a contract extension with the club, keeping him until 2022. At the end of the 2017–18 season, Halstenberg went on to make twenty–three appearances and scoring two times in all competitions.
At the start of the 2018–19 season, Halstenberg was sidelined with injuries, as he returned to training in July. It wasn't until on 23 September 2018 when he made his first appearance of the season, coming on as a late substitute, in a 1–1 draw against Eintracht Frankfurt. Since returning to the first team, Halstenberg regained his first team place, playing in the left–back position. In addition to playing in the left–back position, he also plays in the left–midfield position in a number of matches. It wasn't until on 1 February 2019 when Halstenberg scored his first goal of the season, as well as, setting up the second goal, in a 3–1 win over Hannover 96. In the quarter–finals of DFB-Pokal, he scored his second goal of the season, in a 2–1 win over FC Augsburg on 2 April 2019. Eighteen days later, on 20 April 2019, Halstenberg scored twice for the side, in a 2–1 win over Borussia Mönchengladbach. He started the whole game in the final against Bayern Munich, as RB Leipzig lost 3–0. At the end of the 2
Marcel Halstenberg