Born in Hawthorne, California, Zardes was part of the LA Galaxy youth academy before playing college soccer for Cal State Bakersfield.

[14] With his brace, Zardes made Major League Soccer history, passing Diego Fagúndez to become the highest scoring Homegrown Player in a single season.

[17] On January 20, 2018, Zardes signed for Columbus Crew SC in a swap deal that saw Ola Kamara head in the opposite direction.

[19] In response to Zardes missing the game, he garnered high praise from then Columbus coach Gregg Berhalter, who said “[a]bsolutely he should be,” “the work he does for the team has been outstanding.

[23] Zardes scored a brace against New York City FC on July 6, 2024 at Q2 Stadium, taking him into the Top-10 all-time leading scorers in MLS with 105 career goals.

[25] After a breakout 2014 season in which he scored 19 goals across all competitions, he received his first ever international call up to represent the United States in January 2015, for matches against Chile and Panama.

[29] Zardes was named to the 2015 CONCACAF Gold Cup roster and started in several matches, including a group stage fixture against Haiti where he provided the game-winning assist to Clint Dempsey one minute after coming on as a substitute at halftime.

[30] He scored his first international competitive goal on July 18, 2015, in the Gold Cup quarterfinals against Cuba that ended in a 6–0 victory for the United States.

[31] Zardes was called up in the early stages of 2018 FIFA World Cup qualification for the U.S. and scored the fifth goal in a 6–1 victory over Saint Vincent and the Grenadines on November 13, 2015.

[34] Zardes played in the 2017 CONCACAF Gold Cup and did not score in the tournament, instead providing an assist to Jordan Morris in a narrow 3–2 victory over Martinique in the group stage.

[36] Zardes joined the U.S. in the 2019 CONCACAF Gold Cup and scored the third of four goals in the team's opening group stage match against Guyana.

[38] Zardes scored the game winner in the semifinal match against Qatar in the 2021 CONCACAF Gold Cup in the 86th minute of play off of a cross from Nicholas Gioacchini.