While in high school, Vendt swam for the Ocean State Squids club team under head coach Joshua Stern.

At the 2004 Summer Olympics, Vendt won silver at the 400-meter individual medley, losing only to Michael Phelps who set a world record, in Athens, Greece.

Vendt returned to train at Club Wolverine under Bob Bowman, alongside Klete Keller, Michael Phelps and Peter Vanderkaay.

Vendt won a gold medal in the 2008 Olympics in Beijing by swimming in the preliminary heats of the 4×200-meter freestyle relay.

Vendt currently resides in Boston MA, and works for the wearable sports optimization company, WHOOP.