Marzullo began diving at a young age and has seen success almost his entire life. Landon won the one-meter competition at the 2003 Winter Junior Nationals and followed that up by winning both the one-meter and three-meter events at the 2004 Winter Junior Nationals. He then went on to win the one-meter and platform events and posted a second place finish in the three-meter at the 2005 Summer Junior Nationals.
Marzullo continued to perform well throughout high school and started to take part in international competitions as he won the platform, placed fourth in the one-meter and finished sixth in the three-meter at the 2005 Junior Pan-Am Championships. Earning a spot on the U.S. National team in 2005, he placed fourth in the one-meter and sixth in the platform at the 2005 Senior Nationals. In 2006, Marzullo became the Ohio state champion in the one-meter, and also placed second in the one-meter and fifth in the platform at the 2006 U.S. Open.
Beginning his college career at Indiana, Marzullo wasted no time in becoming the 2008 Big Ten Diver of the Year. He was also named 2008 Big Ten Diver of the Championships in winning both the one-meter and three-meter events while finishing fourth on the platform. He went on to place fourth in the one-meter at the NCAA Championships, while taking 11th and 13th in the three-meter and platform, respectively, to become a three-time All-American in his first year of collegiate competition.
In 2009, he posted a fifth-place finish on the platform and a 12th-place finish in the one-meter at the NCAA Championships. He also won numerous events throughout the season, including setting a new pool record with 402.40 points in the three-meter at the Hoosierland Invitational.
Transitioning to Florida State in the fall of 2009 was no problem for Marzullo as he won the one-meter and three-meter events in his first competition of the year. He went on to earn All-ACC honors by taking third in the one-meter at the ACC Championships. He earned Honorable Mention All-American accolades with a 15th-place finish in both the one-meter and three-meter competitions at the NCAA Championships. Marzullo also competed at the U.S. National Championships, placing second in the one-meter.
In his final season of collegiate diving, Marzullo had many top-3 finishes and was named the ACC Performer of the Week for winning both the one-meter and three-meter events in the final home meet of the season against Clemson. He had an incredible 2011 ACC Championships, placing second on all three boards and garnering All-ACC honors. At the 2011 NCAA Championships, he finished 7th in the three-meter and 15th in the one-meter to earn All-American and honorable mention honors, respectively.
Marzullo was named to the 2011 World University Games diving team and competed in the one-meter and three-meter spring boards as well as the 10-meter platform. His best finish was in the three-meter synchronized event where he placed fourth.
The World Championship Trials start on Wednesday, May 15 at 10 a.m. at the Morcom Aquatics Center.