Parents both played recreationally and was introduced into the sport at a very young age. He would hit with his family at their community courts in Irvine, Calif Was coached primarily by his father, Khuong, until he was brought into the USTA player development program around age 10-11 Mother, Huyen, is a school teacher; has one older sister, Justice Says winning the the Boys' 18s National Hard Courts at the ages of 16 and 17 have been major stepping stones in his career Considers backhand as best shot and favorite surface is hard courts Favorite tournament is Indian Wells and played in qualifying draw earlier this year and lost in 1R to Garin 7-5 7-6(7) Good friends with countryman Alex Michelsen Carlos Alcaraz inspired Tien to compete at a higher level and watch more tennis

Broke into Top 200 in August 2024, Top 100 in January 2025, Top 50 in August 2025 and achieved career-high No. 28 in November 2025 after winning 1st ATP Tour title in Metz

Became the youngest American man to break inside Top 50 since Roddick in 2002

Upset No. 5 Medvedev en route to 2025 Australian Open 4R as Q to be youngest man to defeat a Top-5 player at that event in PIF ATP Rankings history (since 1973) and No. 2 Zverev for biggest win of career to reach 2025 Acapulco QF

Qualified for 2024 Next Gen ATP Finals, defeating Top-3 seeds, No. 1 Fils and No. 3 Mensik in RR and No. 2 Michelsen in SF to become 1st left-handed finalist in event history

Went on a 28-match winning streak from May to July 2024, capturing ITF Tour titles at M15 San Diego twice, M15 Rancho Santa Fe, M15 Lakewood and biggest title of career – 1st Challenger title in Bloomfield Hills

Defeated countryman No. 10 Shelton at 2025 Mallorca to become youngest American man to record a Top 10 win on grass in PIF ATP Rankings history

Received 2022 and 2023 US Open WCs after winning 2022 and 2023 USTA Boys' 18s National Championships and 2024 US Open WC by winning US Open Wild Card Challenge

Peaked at No. 4 in juniors, highlighted by runs to junior finals of 2023 Australian Open (l. to Blockx) and US Open (l. to Fonseca) and defeated Blockx/Fonseca to capture 2023 Australian Open boys’ doubles title w/C. Williams

Played a semester of college tennis at University of Southern California before turning pro in summer of 2023