|Behind the scenes|
|First Appearance:||Tintin in America|
|Last Appearance:||Tintin in America|
He claims to have an amazing sixth sense for solving crimes. While looking for Snowy he gave Tintin another woman's dog, named Fritzy. The woman hit MacAdam over the back of the head and took her dog back. Despite being appreciative for his efforts, Tintin eventually dismisses MacAdam and manages to find Snowy himself.
- He might be the American version of Thompson and Thompson because like them he is clumsy and incompetent at doing his job.