The Polish import capped off a stellar A-League season by picking up the Best Player honour at Dolan Warren Awards at The Star, Sydney, on Monday night.
Mierzejewski comfortably won the award, receiving 37 points from a panel that included former professional players, technical experts, match officials and media representatives.
He was followed by Dimitri Petratos (Newcastle Jets – 26 points), Leroy George (Melbourne Victory – 26 points), Bobo (Sydney FC – 24 points) and Isaias (Adelaide United – 20 points).
The 31-year-old who scored 13 goals and notched nine assists during the regular season was a key player in the Sky Blues winning their second straight premiership.
“I’m delighted to have won the Johnny Warren Medal,” Mierzejewski said.
“To have been voted the Hyundai A-League’s best player is a great honour and very humbling but I couldn’t have achieved this award without all my fantastic teammates.
"They have helped me and my family settle into Sydney and their hard work allows me to go out each week and play my natural game."
After being dumped out of the finals by Melbourne Victory, the reigning Champions were able to console themselves with a host of awards.
Head Coach Graham Arnold was voted the Coach of the Year for the second successive season after ensuring Sydney FC became the first team in history to win back to back Premiers Plates.
Brazilian striker BobĂ´ secured the Golden Boot after becoming the highest ever goalscorer in a Hyundai A-League season with his 27 goals in 27 games.
W-League striker Lisa De Vanna took out the Westfield Goal of the Year Award for her superb curling strike against Canberra United at Allianz Stadium.
And Sydney FC’s A-League team won the Fair Play Award with club captain Alex Brosque picking up the gong on behalf of the squad.
Mierzejewski becomes the second successive Sydney FC player to receive the award, after Milos Ninkovic was crowned the country’s best player last season.
“I would also like to pay thanks to our Head Coach Graham Arnold, as well as all the coaching and medical staff at Sydney FC. They are the best staff in Australian football," Mierzejewski said.
“Finally I want to thank my family and the Sydney FC members for their support and belief in us this season.
“They are the most important thing for me and their backing has helped me to achieve everything I have this year.”
Arnold paid testament to Mierzejewski’s talent and praised his Premiership winning winger.
“Adrian has had an outstanding season and he is very deserving of this high award,” Arnold said.
“To come to a new country and league and to perform as he has done in his first season is a remarkable achievement.
“He has shown what a top class player he is and he has been a key part of our success this season.
“It’s a great honour for Sydney FC to have won this award for the second year in a row and long may it continue.”