Loewen attended Lahainaluna High School in Lahaina, Hawai'i. He is son of former NFL offensive lineman Chuck Loewen, who played for the San Diego Chargers from 1980 to 1984.
Loewen signed with the New Orleans Saints as an undrafted free agent on May 2, 2016.  He was placed on the reserve/non-football injury list on June 6, 2016, prematurely ending his rookie season. 
In Week 2 against the Patriots, Loewen suffered a high-ankle sprain and was placed on injured reserve on September 20, 2017.