Brenden Aaronson

After showing a strong rookie season, Aaronson received his first senior call-up to the United States men's national soccer team in October 2019 for CONCACAF Nations League matches with Cuba and Canada. He did not earn a cap in either match. Aaronson earned his second call-up to the senior team for the 2020 January camp. Aaronson earned his full debut in a 1–0 win over Costa Rica. Later that year, Aaronson scored his first senior international goal during a 6–0 victory over El Salvador in December 2020. Aaronson was included in the 26-man squad for the 2022 FIFA World Cup, playing in all three group games. On May 26, 2026, Aaronson was selected in the 26-man squad for the 2026 FIFA World Cup.

Bethlehem Steel

Aaronson appeared as an academy player playing for Bethlehem Steel FC during their 2017 season after coming through the Philadelphia Union academy. On September 30, 2017, Aaronson made his first start for Steel FC in an away draw versus Tampa Bay Rowdies. Aaronson made 21 appearances for Steel FC and scored his first goal for the professional side against Atlanta United 2.

Philadelphia Union

On September 17, 2018, it was announced that Aaronson would join the Philadelphia Union at the beginning of their 2019 season. On March 17, 2019, the homegrown player scored his first professional goal in his MLS debut, helping Philadelphia tie against Atlanta United. Considered to be a back-up playmaker for the Union, injuries and suspensions gave Aaronson the opportunity to start and excel in the first team as both playmaking number 10 and left-sided box-to-box midfielder. At the end of his rookie season, Aaronson finished second for the 2019 MLS Rookie of the Year Award, with three goals and two assists in over 1,640 minutes played. Aaronson was the youngest player out of the five finalists. The 2020 season became a breakout year for Aaronson who finished the season with 31 appearances across all competitions and scoring 4 goals. Aaronson's performance during the season earned him several accolades include being named to the 2020 MLS Best XI for the regular season and the MLS is Back Tournament. The Union finished the season with the best league…

His younger brother Paxten Aaronson is also a professional soccer player and plays for Major League Soccer club Colorado Rapids. Aaronson's performances for the Philadelphia Union and Red Bull Salzburg earned him the nickname of the "Medford Messi", an alliteration that refers to his birthplace and makes a comparison with Argentine player Lionel Messi. He is a fan of the San Francisco 49ers, as his father is from Sacramento. He became engaged to Milana D'Ambra in August 2024. They got married in 2026.

Raised in Medford, New Jersey, Aaronson attended Shawnee High School for a single year before being selected to the Philadelphia Union's YSC Academy, where he played soccer and completed his high school education. During his time at YSC Academy, Aaronson had played for Union's youth teams before committing to Indiana University and signing an amateur contract with Bethlehem Steel FC.