The loss was the Cyclones' first home-opener defeat in 20 years.
Brett Prahl scored 14, Bryce Nze 13 and Bryce Barnes 10 as the Panthers (2-0) overcame an early eight-point deficit to take a seven-point halftime lead at 39-32.
Milwaukee, of the Horizon League, extended its lead to nine early in the second half but the Cyclones battled back to get within two at 41-39 on Zoran Talley Jr.'s 3-point play with 15:45 to play.
An 11-2 spurt sparked by Nze and Stull put the Panthers back up by nine at 52-41. The lead grew to 13 on a pair of free throws from Barnes and the Panthers cruised to the win.
The Cyclones would only get as close as 11 the rest of the way.
Jeff Beverly and Nick Weiler-Babb each scored 11 points to lead the Cyclones, who fell to 0-2.
Iowa State struggled from the field, connecting on only 16 of 42 field-goal attempts (38 percent). From beyond the arc, the Cyclones made only 3 of 15 (20 percent).
The Panthers were good on 7 of 19 tries from 3-point range (37 percent) and from the field they made 48 percent (24 of 50).
The Panthers controlled the paint, outscoring the Cyclones, 30-20.
Iowa State committed a whopping 18 turnovers, which Milwaukee converted into 19 points.
Milwaukee was coming off a 10-point win against Wisconsin-La Crosse while Iowa State lost to Missouri in its season opener.