Maštalír studied theatre acting at the Academy of Performing Arts in Bratislava, graduating in 2000.

[2] In addition to theatre acting, Maštalír has starred in television series, including Za sklom (2016), Chlap (2022), Vedlejší produkt (2024).

He also appeared in the joint Czech and Slovak adaptation of the show Call My Agent!

He is also active as a film actor, notably appearing in the movies The Line (2017), Bet on Friendship (2021) and Waves (2024).

[1] As an acting student, Maštalír was in romantic relationship with the actress Diana Mórová, who is 8 years his senior.