The contract also includes a team option for a fifth year.
The 6-foot-4, 240-pound Louisiana State product was the No. 6 overall pick in the 2013 NFL Draft.
Mingo played in 40 games for LSU between 2010-12, recording 119 tackles, 15 sacks, four forced fumbles and three fumble recoveries.
The Browns have now signed all of their draft picks.
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Adam Forsgren, EastIdahoNews.com Columnist
Millie Behra, FamilyShare
Katelyn Carmen, FamilyShare
Billy Hallowell, Deseret News