The strong arm robbery took place near the corner of West Argyle Street and North Winthrop Avenue, around 7:18 p.m.
The initial police dispatch report indicated the offender threatened the victim during the robbery. Authorities also said the victim recognized the robber from the neighborhood.
The crook was described as a black male in his late teens or early twenties, with a bald or shaved head.
After the robbery, the suspect was seen walking westbound on Argyle Street from Winthrop.
At 7:37 p.m., police arrested the cell phone thief at the Windy City Ribfest in Uptown, near Lawrence and Broadway.
It appears police recovered the victim's iPhone.