On January 19, 2018, Barlow was drafted in the second round of the 2018 MLS SuperDraft, by the New York Red Bulls.[7] On March 15, 2018, he signed his first professional contract with New York Red Bulls II.[8] On May 27, 2018, he scored his first goal for New York in a 4–1 victory over Indy Eleven.[9] On August 25, 2018, Barlow recorded a second half hat-trick to help New York to a 4–4 draw with Charleston Battery after trailing 3–0 at halftime.[10] On October 20, 2018, Barlow helped New York advance in the 2018 USL Playoffs, scoring the loan goal in a 1–0 victory over Charleston Battery.[11]
On March 9, 2019, Barlow scored two goals in a 3–1 victory over Swope Park Rangers in the first match of the season.[12] On July 10, 2019, he scored two goals to help New York to a 4–3 victory over Bethlehem Steel.[13] He ended the season scoring 11 goals in 16 matches for the USL Championship squad in 2019.
New York Red Bulls
On May 8, 2019, Barlow was signed to a first team contract with New York Red Bulls.[14]
On May 19, 2019. Barlow scored his first goal for the first team on his debut in a 1–0 victory over Atlanta United. With the Red Bulls down to ten men he scored his first career MLS goal against Brad Guzan.[15] He ended his first season with the first team scoring 5 goals in 14 appearances.
On September 27, 2020, Barlow scored two goals in a 4–1 victory over Montreal Impact.[16] On February 26, 2022, Barlow scored the third goal for New York in a 3–1 victory over San Jose Earthquakes in the opening match of the season.[17] On May 25, 2022, Barlow scored in a 3–1 victory for New York over Charlotte FC as his team advanced to the quarterfinals of the 2022 U.S. Open Cup.[18] On 24 July 2022, Barlow scored the winning goal for New York in a 4–3 victory over Austin FC at Q2 Stadium.[19]
On April 8, 2023, Barlow scored an injury time equalizer to help New York to a 1–1 draw with San Jose Earthquakes.[20] On May 31, 2023, Barlow scored the lone goal for New York in a 1–0 victory at Inter Miami.[21] On October 7, 2023, Barlow scored the opening goal for New York in a 3–0 victory over Toronto FC, helping his club keep its playoff hopes alive.[22] On October 25, 2023, Barlow scored for New York in a 5–2 victory over Charlotte FC, helping his club advance to the first round of the 2023 MLS Cup Playoffs.[23]