Valkusz was the winner of the 2015 Yucatán Cup, a Grade 1 event in Mérida and the Canadian Open Junior Championships in Repentigny.

[2] He won his first Challenger title defeating Francisco Comesaña at the 2023 Macedonian Open and reached the top 225 in the rankings on 29 May 2023.

[2][3] He entered the 2023 Moselle Open as lucky loser and defeated ninth seed Daniel Altmaier in the first round, for his first ATP win.

[6] Valkusz's match record against players who have been ranked in the top 100, with those who are active in boldface.

ATP Tour, Challenger and Future tournaments' main draw and qualifying matches are considered.