Leckie told Hertha's website that the club first made contact about his services mid-season and that the capital-based outfit's recent success convinced him to make the move.
While details of the transfer and contract length remain unconfirmed, the German football magazine kicker has reported Leckie has signed a four-year deal after Hertha paid Ingolstadt €3million for the 26-year-old.
Leckie has spent the past six seasons in Germany, including the last three years with Ingolstadt, who were relegated to the 2. Bundesliga over the weekend.
Hertha finished sixth, meaning they will play in the Europa League's third qualifying for the second straight year.
"I had a few offers. Hertha stood out for various reasons," Leckie said.
"Hertha is a big, fantastic Bundesliga club. They’ve been very successful over the last two seasons. Now they're playing in the Europa League.
"Additionally, Berlin is great; one of the nicest cities in Germany. I also think that Pal Dardai is a great coach, who I can learn a lot from."
The Australian added: "Last winter it was reported in the newspaper that I was a potential candidate for Hertha. That was the first time I heard the rumour.
"My agent then got in touch with the club, but at this point I was solely focussing on Ingolstadt.
"Then towards the end of the season, particularly in the last two weeks, the talks intensified.
"I met with Michael Preetz and Pal Dardai for the first time last Monday. We talked extensively and I was pleased because I realised that the club really was interested in me."
Mathew Leckie, Ingolstadt
Leckie's speed was a critical factor for Hertha coach Pal Dardai.
"Mathew Leckie is a versatile player and has shown that he has the pace to bomb up and down the flanks, and that'll benefit us a lot when it comes to attacking," Dardai told Hertha's website.
Leckie played 30 of 34 games for Ingolstadt this season, notching three assists.
The ex-Adelaide United forward leaves Bavarian club after 10 goals in 96 appearances, while he has also previously played for FSV Frankfurt and Borussia Monchengladbach.