The attack happened shortly after 8 p.m. Sunday, May 19, in Albany, outside the Salvation Army building on Clinton Avenue.
When officers arrived, the 60-year-old victim told them that a man had punched him several times in the face and head, knocking him unconscious. The culprit then stole his wallet and fled the scene.
The victim was taken to Albany Medical Center Hospital and treated for injuries to his face.
A description of the suspect was put out over police radio, and he was spotted a short time later at a bus stop near Washington Avenue and North Hawk Street.
Daniel-Dyel Thomas, age 22, was arrested without incident on suspicion of second-degree robbery.
Police said Thomas and the victim know one another and the attack was not random.
Click here to follow Daily Voice Schaghticoke and receive free news updates.