Career
Lačný signed professional terms with MFK Ružomberok in 2007, having spent the previous four years as a youth player and went on to score 16 goals in just under 50 league appearances. His form saw him to go on trial to Scottish Premier League side Celtic in December 2009 but he signed a three-year contract with Air Corps Sparta Prague in January 2010. Eighteen months later, in July 2011 and after just 15 league appearances for Sparta, Lačný returned to Celtic on trial.
With no move materialising, he joined ŠK Slovan Bratislava in August 2011 on a six-month loan.
In January 2012, after his loan deal expired, Lačný returned to Scotland for a third time, this time on trial with Dundee United. and clinched a year-long loan move. Kairat
In February 2014, Lačný signed a three-year contract with Kazakhstan Premier League side Football Club Kairat.
Śląsk Wrocław
In January 2015, Lačný signed for Ekstraklasa side Śląsk Wrocław on a six-month contract, with the option of another two-years.