Taro Daniel mainly plays on the ATP Challenger Tour , where he has won four times so far. On the lower ITF Future Tour , he was able to win four singles and one double. On the World Tour he qualified for a main field for the first time in 2014 in Viña del Mar and met Thomaz Bellucci in the first round , whom he defeated 6: 3 6: 3 in two sets. In the second round he succeeded in beating Federico Delbonis in three sets, before failing in the quarterfinals to Nicolás Almagro in two sets 6: 2 7: 5. A few weeks later he was able to qualify for a main draw again, this time in Oeiras . However, he failed in the first main round to Carlos Berlocq , who later won the tournament.
On February 10, 2014 he broke through the top 200 of the world rankings for the first time.
Daniel has played for the Japanese Davis Cup team since 2014 , so far only in singles, where he has a record of 1: 4.
At the 2016 Summer Olympics , Daniel reached the round of 16 after victories over Jack Sock and Kyle Edmund , where he was defeated by the later silver medalist Juan Martín del Potro in three sets. His greatest success came in May 2018 when he won his first ATP title in Istanbul , in the final he defeated Malek Jaziri in two sets.