The Australian smashed home the loose ball seven minutes before half-time after a brilliant advantage was played by debutant female referee Bibiana Steinhaus.
His goal wasn't enough for Hertha as Bremen's Thomas Delaney restored parity mid-way through the second half.
It was Leckie's third goal in three Bundesliga games for Hertha this campaign - a huge improvement on last season after failing to score in his last 30 top-flight matches for Ingolstadt.
Fellow Socceroo Robbie Kruse was also in the goals, scoring an 86th minute winner for Bochum in their 2-1 victory away at Darmstadt in Bundesliga 2.
Bochum trailed by a single goal with nine minutes to play before Dimitrios Diamantakos struck an equaliser and Kruse secured all three points.
Australian striker Jamie MacLaren was an unused substitute for Darmstadt.