Gavin Andresen is a software developer most known for his involvement with bitcoin. While he was working on 3D graphics and virtual reality software, Andresen got involved in the bitcoin development and was declared by Satoshi Nakamoto as the lead developer of the project after he announced his departure. Once Gavin found out about a secure digital currency that has no owner and it's peer to peer, he considered it brilliant and contributed to it. He created the first bitcoin faucet which was giving away bitcoins for free. He stopped working on it in February of 2016 and stepped back as a lead maintainer.
It is considered that a reason why Satoshi left the community was because of him. In April of 2011, Gavin emailed Satoshi saying that CIA wants to know more about this project so they invited them to speak on an event. This is the last confirmed message corresponding to Satoshi Nakamoto in which he/she/they reply/replies to Andresen:
I wish you wouldn’t keep talking about me as a mysterious shadowy figure, the press just turns that into a pirate currency angle.
Maybe instead make it about the open source project and give more credit to your dev contributors; it helps motivate them.
In May 2016, Andresen stated that an Australian programmer and entrepreneur, Craig Wright, was Satoshi Nakamoto, but later regretted that statement. There is a conspiracy theory that Gavin Andresen is Satoshi Nakamoto, but of course it is extremely unlikely.