Youth, college and amateur

Mocyunas attended University High School, where he was named West Virginia Midfielder of the Year, First Team All-State and helped the team to runner-up in the state tournament. He also played club soccer for Arsenal FC of Pittsburgh for three seasons and was named Player of the Year.^[1][2][3]

In 2017, Mocyunas attended Marshall University to play college soccer. Here he stayed until 2022 due to a redshirted freshman season and the COVID-19 pandemic that delayed the 2020 season. Over his college career, Mocyunas made 92 appearances for the Thundering Herd and scored a single goal. In his junior year, he helped the team to be College Cup National Champions, also earning United Soccer Coaches Scholar All-Region honors and Second Team All-Conference USA honors.^{[1][4][5][6][7]}

While at college, Mocyunas also played in the USL League Two, spending two non-consecutive seasons with West Virginia United in 2019^[8] and 2022,^[9] and a single season with South Bend Lions.^[10]

Professional

On January 13, 2023, Mocyunas signed a two-year deal with USL League One side South Georgia Tormenta.^[11][12]