Michael was adopted Tuesday in Phoenix, according to ABC News.
Before the adoption, Tara Montgomery told ABC News that Michael had been living with his family for more than a year.
"Michael was placed with us on Feb. 14, 2015, when he was 18 months old. We were his third foster family," Montgomery said.
"His original case plan was reunification with his 'bio-mom.' When that plan failed, a new plan was set. As a single parent, I was not looking to adopt, just to help kids during transition."
The picture taken of Michael right after the adoption became official has since gone viral. It has been retweeted more than 50,000 times and has more than 130,000 likes.
"This photo is the definition of his personality," Montgomery said. "He couldn't help but let everyone know that he was being adopted today. We are so happy to have Michael in our lives."