His international career began with Germany U16s and U17s. In September 2012, Green represented the United States at the U18 level in an international friendly with Netherlands, scoring in a 4–2 victory.
Green was called up to the United States senior team by head coach Jürgen Klinsmann for friendlies in November 2013, but he declined the call due to being ineligible to play unless a one-time switch – allowed for players with dual nationalities - was filed, something he said he was not ready to do. Instead he joined the German U19 team for a friendly against France.
On July 1, 2014, Green became the youngest player in U.S. history to score in the World Cup, scoring with a volley in the 107th minute with his first touch of the ball, less than two minutes into his debut game against Belgium in the round of 16. With the goal, he became the youngest player to score at that World Cup.
On August 20, 2015, Green was demoted to FC Bayern Munich II. He made his first appearance of the season playing right back in a match on August 21, 2015 against SV Schalding-Heining. On October 23, 2015, Julian Green scored a hat trick against FC Augsburg II. Green started a Champions League match for Bayern Munich against Dinamo Zagreb, playing 62 minutes. It marked Green's first appearance with the first team in over two years.
Green returned to the first-team after new manager, Carlo Ancelotti, included him in the preseason squad. During the second game of their U.S. tour, Green scored a hat trick in the first 35 minutes, helping Munich to a 4–1 win over Inter Milan. Following an international break in which Green scored two goals in two successive matches, Ancelotti hinted that Green could be receiving a "chance to play in the next few games". That chance came on October 26, 2016, when Green scored his first competitive goal for Bayern, coming against FC Augsburg in a 3–1 victory in the second round of the DFB-Pokal. With the goal, Green successfully became the first American to score a goal for Bayern. To that point in the season, despite being regularly named to the squad for Bundesliga matches, Green had only made a substitute appearance in the Pokal, against first round opponent FC Carl Zeiss Jena.
On August 31, 2017, Green was loaned out to SpVgg Greuther Fürth until the end of the season.
