Avena relocated from Southern California to Las Vegas in 2004 to work as a security guard for the Hard Rock Hotel & Casino and later made his professional MMA debut in 2005.
Avena made his promotional debut at WEC 25 against Logan Clark on January 20, 2007.
Avena made his next appearance at WEC 35 against Dave Terrel on August 3, 2008 and won via first-round TKO.
Avena made his promotional debut against Lenny Lovato February 28, 2013 at Bellator 91 and won via first-round knockout.
On the morning of May 4, 2016, Avena's body was discovered by police in his Las Vegas apartment.