Sean Nealis (born January 13, 1997) is an American professional soccer player who plays as a defender for Major League Soccer club D.C. United.
Born in Massapequa, New York, Nealis began playing soccer at the age of seven. In his junior year of high school, he led the Massapequa Chiefs to a NYSPHSAA Class AA Championship. Nealis attended Hofstra University, where he was a member of the varsity soccer team for four years. During his senior season he was recognized as the Colonial Athletic Association Defensive Player of the Year. In 2018, Nealis played five games in the PDL with Westchester Flames.
He is the younger brother of former Georgetown Hoyas, Long Island Rough Riders and New York Cosmos defender, Jimmy Nealis. His older brother, Connor, played for Binghamton University. Nealis' younger brother, Dylan, was a member of the Georgetown Men's Soccer National Championship Team in 2019 and was drafted third overall by Inter Miami in the 2020 MLS SuperDraft. Dylan later joined his brother as a Red Bull in 2021.
On January 11, 2019, Nealis was drafted in the second round of the 2019 MLS SuperDraft, by the New York Red Bulls. After a strong preseason with the club, Nealis signed an MLS contract on February 17. On February 27, 2019, Nealis made his professional and New York Red Bulls debut coming on in the second half for Aaron Long in 3âÂÂ0 victory over Atlético Pantoja in the 2019 CONCACAF Champions League. A few days later, on March 2, 2019, Nealis made his league debut with the club, appearing in a 1âÂÂ1 draw with Columbus Crew. On May 11, 2019, Nealis scored his first goal for the club in a 3âÂÂ1 victory over FC Dallas.
Nealis became a regular starter for New York during the 2021 season. On August 25, 2021, he signed a three-year contract extension, with an additional option year. On October 23, 2021, Nealis scored the winning goal for New York in a 2âÂÂ1 victory over Columbus Crew.
Toward the end of the 2022 season, New York once again handed Nealis a contract extension through the 2026 season with an option for 2027. Nealis was named team captain for New York for the 2023 season. On September 23, 2023, Nealis scored his first goal of the season, the go ahead goal in a 5âÂÂ3 victory over D.C. United.
Nealis scored the only Red Bull goal in a 2âÂÂ1 loss to the LA Galaxy in MLS Cup 2024. On May 7, 2025, Nealis scored his first goal of the season for New York in a 4âÂÂ1 victory over Colorado Springs Switchbacks FC, helping his club advance in the U.S. Open Cup.
On 22 December 2025, D.C. United acquired Nealis from New York Red Bulls in exchange for $350,000 in General Allocation Money (GAM) ahead of the 2026 season.