[8] Since joining the club, Halstenberg became a regular in the starting eleven at Borussia Dortmund II.

[10] It wasn't until on 28 March 2012 when he scored his first goal for Borussia Dortmund II, in a 4–2 win over Eintracht Trier.

[11] Halstenberg later added more goals to his tally, scoring against TuS Koblenz and SC Verl.

[14] It wasn't until on 3 August 2012 when he scored his first Borussia Dortmund II goal of the season, in a 1–1 draw against Alemannia Aachen.

[17] Despite this, Halstenberg continued to feature for the Borussia Dortmund II side for the remainder of the 2012–13 season.

[21] Since making his FC St. Pauli debut, he quickly established himself in the starting eleven, where he faced competition from another left–back position player, Sebastian Schachten.

[24] In a follow-up match against Union Berlin, he played a vital role when he set up two goals, as FC St. Pauli won 2–1.

[28] After returning to the reserve team from injuries, he made his first appearance of the season, starting the whole game, in a 4–1 loss against RB Leipzig.

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).

[41] Halstenberg made his RB Leipzig debut, starting the whole game, in a 2–0 win over Paderborn 07 on 11 September 2015.

[43] 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.

[46] Despite being sidelined later in the 2015–16 season,[47] Halstenberg remain featured in the first team, as he played nearly every minute of Leipzig's successful campaign in the 2.

[54] 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.

[58] He made his UEFA Champions League debut, starting the whole game, in a 1–1 draw against AS Monaco on 13 September 2017.

[64] 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.

[69] Eighteen days later, on 20 April 2019, Halstenberg scored twice for the side, in a 2–1 win over Borussia Mönchengladbach.

[73] Halstenberg made his international debut on 10 November 2017 for Germany in a friendly match against England, starting as a left back and played the whole game, as they drew 0–0.

[74] It wasn't until on 20 March 2019 when he made another appearance for Germany, coming on as a substitute, in a 1–1 draw against Serbia.

[78] The pair played against each other, as Borussia Dortmund II won 7–1 against his brother's team, SC Wiedenbrück on 29 August 2011.

[80] In February 2016, while on the sidelines due to injury, Halstenberg caused controversy when he took a selfie with his girlfriend at the Holocaust Memorial.