On September 25, Systrom and Krieger announced their resignations as chief executive officer and chief technical officer of the Facebook-owned company.
Instagram was founded in 2010 and sold to Facebook for a billion dollars two years later.
Systrom and Krieger are officially leaving Instagram as of October 1.
For almost 10 years, Kevin Systrom and Mike Krieger have led Instagram, first independently, then later as a bright spot in the greater Facebook hellscape.
In his blog post, Systrom praised Mosseri's "strong design background and a focus on craft and simplicity - as well as a deep understanding of the importance of community".
Mosseri, according to his LinkedIn profile, joined Facebook as a product designer in July 2008, working his way up the corporate ladder over the years. At Facebook he worked on the company's mobile product and news feed before moving over to Instagram.
The new head will be tasked with rebuilding the company's executive team, and will hire new heads of engineering, product, and operations. In the post, the duo said that in their absence, they hope Instagram keeps the community front and center in everything it does.
"I'm humbled and excited about the opportunity to now lead the Instagram team". "We believe that Adam will hold true to these values and that Instagram will continue to thrive", they added. Systrom and Krieger were widely reported to have been unhappy with recent changes Facebook was making to the Instagram app and business. Facebook CEO Mark Zuckerberg has also wielded Instagram Stories as the most devastating weapon in his ongoing war against Snapchat, as Instagram's live story feature has long-since eclipsed Snapchat's entire active user base. Although Facebook doesn't break out Instagram's revenue, it has been estimated that the division will generate about $8 billion in revenue in 2018, according to EMarketer data.