Kimmich played youth football for VfB Stuttgart before joining RB Leipzig in July 2013. Stuttgart secured an option to rebuy. He made his 3. Liga debut for the club on 28 September of that year, as a substitute for Thiago Rockenbach in a 2–2 draw with SpVgg Unterhaching. He scored his first professional goal in a 3–2 victory over 1. FC Saarbrücken on 30 November 2013. He finished the 2013–14 season with one goal in 26 appearances.

On 2 January 2015, Kimmich agreed to join Bayern Munich on a five-year contract which lasts until 30 June 2020, for a reported fee of €7 million, most of which went to VfB Stuttgart. He made his debut for the club on 9 August, starting in the first round of the DFB-Pokal against FC Nöttingen. Pep Guardiola gave him his Bundesliga debut the following month on 12 September when he entered play as a late substitute at home against FC Augsburg. Four days later, Kimmich made his first appearance in the UEFA Champions League in Bayern’s tournament opener away at Olympiakos and he started in the Bundesliga for the first time three days thereafter, playing 90 minutes against SV Darmstadt 98 in a 3–0 victory.

Kimmich ended his first season at Bayern having made 23 league appearances of which 15 were starts. He also played the full 120 minutes in Bayern’s 2016 DFB-Pokal Final defeat of Borussia Dortmund at the Berlin Olympiastadion on 21 May.

Kimmich started the 2016–17 season by coming on as a substitute in a 2–0 win against Borussia Dortmund in the 2016 DFL-Supercup. On 9 September, he scored his first goal for FC Bayern in a 2–0 Bundesliga, away win at FC Schalke 04. Four days later, he scored his first two Champions League goals in a 5–0 home win against FC Rostov. Kimmich scored a late winning goal in the 88th minute in a 1–0 away victory over Hamburger SV. He finished the 2016–17 season with nine goals in forty appearances.

On 17 May 2016, Kimmich was named in Germany’s preliminary 27-man squad for UEFA Euro 2016. On 31 May 2016, he was named in the final 23-man squad and given the shirt number 21. On 21 June 2016, Kimmich was selected to start for Germany in their final Group C match against Northern Ireland, replacing Benedikt Höwedes at right-back. Kimmich remained Germany’s first-choice right-back as they reached the semi-finals and was named in UEFA’s Team of the Tournament.

On 4 September 2016, Kimmich scored his first goal for the German national team in a 3–0 victory over Norway during 2018 FIFA World Cup qualification.

Kimmich played in the 2017 DFL-Supercup and won the title as Bayern defeated their arch-rival Borussia Dortmund on 5–4 penalties after the extra time ended 2–2. On 16 September, he provided overall three assists to Thomas Müller, Arjen Robben and Robert Lewandowski’s goals to defeat 1. FSV Mainz 05 with a 4–0 victory. On 9 March 2018, Kimmich signed a three-year contract extension which lasts until 30 June 2023. He managed to score each goal in both the first and second leg in the Champions League semi-final tie against Real Madrid, but his side were knocked out from the competition on 4–3 aggregate. Kimmich finished the 2017–18 season with six goals and seventeen assists in 47 appearances.

On 17 May 2017, Kimmich was included in Joachim Löw’s Germany squad for the 2017 FIFA Confederations Cup. He started in all five of the team’s matches at the tournament, registering two assists, as Germany won its first Confederations Cup title.

On 6 June 2017, Kimmich scored from a stunning overhead kick in a friendly against Denmark in the 88th minute of the game which helped Germany to grab their late equaliser against Denmark, as the match ended up 1–1.

On 12 August, Kimmich started the season by playing in the German Super Cup and also won the title as his side defeated Eintracht Frankfurt with a 5–0 victory. The following week, on 18 August 2018, Kimmich played in the 1–0 win against SV Drochtersen/Assel in the first round of the German Cup. Kimmich played in the opening match of the Bundesliga season against 1899 Hoffenheim on 24 August 2018. Bayern won the match 3–1. Kimmich’s first goal of the season came against Hannover 96 on 15 December 2018. He made his 100th league appearance for the club on 9 February 2019 during a 3–1 win over rivals, Schalke.

On 4 June 2018, Kimmich was selected for Germany’s final 23-man squad by Joachim Löw for the 2018 FIFA World Cup. On 17 June 2018, Kimmich made his World Cup debut against Mexico in their opening match, but the game ended in a 1–0 loss for Germany.

On 6 September 2018, Kimmich started Germany’s UEFA Nations League opener against France, playing as a defensive midfielder for the first time in 18 months.

Kimmich has two kids, a son, born in 2019, and a daughter, born in October 2020, with his girlfriend Lina Meyer. He launched an online initiative “We Kick Corona” with his Bayern Munich teammate Leon Goretzka, to help charitable, social or medical institutions during the COVID-19 pandemic.

On 14 August 2020, Kimmich scored one goal and provided an assist in an 8–2 win over Barcelona in the 2019–20 UEFA Champions League quarter-final. On 23 August 2020, Kimmich made an important assist for the winning goal against Paris Saint-Germain by Kingsley Coman in the final, to be his first Champions League title along with his teammate Serge Gnabry, another VfB Stuttgart academy product.

Kimmich started the 2020–21 season by acquiring the number 6 shirt, after Thiago Alcântara who had worn it for seven years. On 30 September 2020, he scored the winning goal in a 3–2 win over Borussia Dortmund in the 2020 DFL-Supercup. On 27 October, Kimmich scored the winning goal in a 2–1 away victory over Lokomotiv Moscow in the 2020–21 UEFA Champions League.