- Bats Left, Throws Right
- Height 5' 11", Weight 165 lb.
Adam attended the MLB European Academy in 2011-2012. In the 2011 European Junior Championship, he hit .227/.393/.273 with 6 runs in 6 games, fielding .938; he tied for 4th in the event in walks. Debuting in the Extraliga at age 17, he was 5 for 14 with two walks, a run and a RBI for Draci Brno as a teammate of his brother. He was 0 for 3 in the postseason as they won a title. In the 2012 European Cup, he was 1 for 2 with a RBI, singling off Rik Geestman to score Pavel Budský. He was 2 for 18 with two walks and a RBI in the 2012 World Junior Championship. In the 2013 U-18 Baseball World Cup, he hit .188/.263/.188.
Hajtmar hit .417/.472/.625 with 15 RBI in 48 AB as a key bench player for Draci Brno in 2013 and was 0 for 1 in the postseason as they won the pennant. In 2014, he batted .365/.389/.423, again with 15 RBI in 18 games, but was 1 for 9 with a walk in the postseason; they won their fourth title in a row. He was 0 for 4 with a walk and two runs in the 2014 European Cup. He was named MVP of the 2014 European U-21 Championship. He produced at a .356/.398/.425 clip and fielded .895 in 2015 as he begun seeing more regular playing time. Starting in left for Draci Brno in the 2015 European Cup, he hit .421/.450/.579, tying Gianison Boekhoudt for 9th in the Rotterdam pool in average, tying Shaldimar Daantji and Riccardo Bertagnon for 6th in total bases (11) and finishing 6th in slugging (between Boekhoudt and Martin Schneider). In the 2015 postseason, he hit .407/.448/.407 but Draci Brno fell short; he was 5th in postseason average, between Jakub Malik and Corey Lyon. He also won MVP honors at Prague Baseball Week.
He made his national team debut at the 2017 World Baseball Classic Qualifiers in March 2016. He saw most of his action in their 15-3 romp of Germany in round 2, pinch-hitting for Michal Ondráček in the third with one on, one out and a 1-0 deficit. He hit into an error by Jan-Niclas Stöcklin and wound up scoring the go-ahead run on a Mike Cervenak single. Staying in the game in left, he finished 1 for 5, singling off Sven Schüller in the 8th (following a hit by his brother) and scoring on a Cervenak double. In his other game, he pinch-ran for Cervenak on third base with one out in the bottom of the 8th and a 4-4 tie against Nicaragua but was stranded and did not stay in to play the field. He scored the first run in the new Euro League Baseball, reaching on an error in the first against Buchbinder Regensburg Legionäre's Mike Bolsenbroek and being driven in by Schneider.