The movie American Graffiti, written and directed by Downey graduate George Lucas, is based in Modesto but filmed in Petaluma, California.

The Agriculture Department at Thomas Downey was first created to work the school's early orchards.

In 2006, the Thomas Downey High boys' varsity had a run n' gun type Offense led by their seniors Zeph Tyson, Andre Poree, Travis Jacobson and Roderick Stevens.

The Downey High Boys Soccer team has won the MMC (Modesto Metro Conference) in 2008, 2010, and 2011, and had a section final appearance in 2007.

Blake Smith (class of 2006) currently plays in the Los Angeles Dodgers organization as an outfielder for the Double A Chattanooga Lookouts.

In 2012, The Thomas Downey High Football team won the Modesto Metro Conference for the first time in school history with a record of 6-0-0.

Downey's Second consecutive MMC Titile was led by 15 All league Players, Offense: QB PJ Wilson, RB Mario Sanchez, Wide receivers Tristan Best, Josh Lowe, and Mike Falepouno, Offensive linemen Kyler Bourque, Michael Dean Barron, and OL Josh Roy.

In 2014, The Thomas Downey High Football team won the Modesto Metro Conference for the third straight year.

In addition, Downey High Cornerback, Jakob Magana was named Sac Joaquin Section defensive player of the year by MaxPreps.

For many years, Downey High had one of the most outstanding band programs in the far western United States.

Things got started under the direction of the band director and composer, Roger Nixon, who later moved on to Modesto Junior College and then San Francisco State University.

Daily band practices for several hours would begin 6 weeks before school even began in the fall.

Several professional and semi-professional musicians graduated from this program including Gary Coates, Ken Nelson, Tony Clemens, Doug Ruby, Joyce Maley, Scott Ferrel and Dave (Fowler) Johnson who attended in the mid 1960s through the early 1970s.