Larry Izzo attended Rice University where he wore the number 26, and was a four-year letterman and standout and finished fourth on the school's all-time tackles list with 301 tackles, setting a school-record 46 tackles for losses, and a season record of 18 tackles for losses in 1995. In 1994 an underdog Rice beat top 10 ranked Texas on national television by the score 19-17, as Izzo was selected player of the game with two key sacks (sharing the honor with teammate N. D. Kalu). It was the first time in over 30 years that Rice had beaten its in-state rival, and would help Rice win a share of the Southwest Conference title for the first time in 37 years. As a senior Izzo was voted defensive team captain and earned consensus All-Southwest Conference honors after registering 121 tackles, he won the George Martin Award as the team’s MVP and won the Jess Neely Defense Award as the team’s top linebacker. Was also selected as an Honorable Mention All-American.
Izzo went undrafted in the 1996 NFL Draft and was later signed by the Miami Dolphins as a free agent in April 1996. He first came to local notoriety based on a sound byte that circulated during the pre-season of Izzo's rookie year, where Miami coach Jimmy Johnson told the team that only two players were guaranteed to make the team: one was Dan Marino and the other the then-unknown Izzo. He spent most of his time on special teams, and was rewarded with his first trip to the Pro Bowl in 2000.
Izzo signed with New England in 2001, and played on three of the four Patriots' Super Bowl championship teams (2001, 2003 and 2004). He also had two more trips to Hawaii as the AFC special team representative in 2002, and 2004. Izzo gained notoriety in 2002 in the Patriots Super Bowl parade by leading the crowd in a "Yankees suck!" chant, in reference to the Yankees-Red Sox rivalry.
Through twelve games into the 2009 NFL season, Izzo has recorded more special teams tackles than any other NFL player in history (298). Izzo has racked up 275 ST Tackles in 200 career regular-season games plus 23 tackles in 21 postseason games. While the NFL does not publish official statistics on ST tackles, that ranks Izzo ahead of Buffalo's Mark Pike (283). He also ranks ahead of Keith Burns (231), Gary Stills (218), former Dallas CowboyBill Bates (216) and former Bill Steve Tasker (186).
In 14 NFL seasons, Izzo never played on a team with a losing record. That included 9 playoff appearances, 5 AFC Championship appearances, 4 Super Bowl appearances, and 3 Super Bowl victories.
Through the 2008 season, Izzo played in 103 consecutive games for the Patriots, dating back to 2002.
For his charity work and community activism, Izzo was honored by Bob Kraft and the New England Patriots Organization with the Ron Burton Community Service Award at the team’s annual Kickoff Gala in August 2008. To date, his Larryoke events have raised over $600,000 for U.S. Military veterans and their families.
Izzo represented the NFL during a 2005 "The USO and NFL Salute the Troops Tour," which visited soldiers in Afghanistan and Iraq. During the tour, Izzo and Warrick Dunn officially opened the USO Pat Tillman Center at Bagram, a center that serves thousands of troops transitioning to and from Kuwait, Qatar, Iraq and Europe.
In October 2006, Izzo hosted a charity event in Boston "Karaoke with Larry Izzo and the New England Patriots." The 2nd annual event raised over $200,000 for charities which included The Intrepid Fallen Heroes Fund, Operation Ensuring Christmas, the USO of New England, and Fallen Patriot. Participating at the fundraiser over the past two years were celebrities and athletes including Mark Cuban, Tom Brady, and other members of the New England Patriots.
While at the 2002 Pro Bowl, Izzo visited 8,500 crew members aboard the USS Carl Vinson at Pearl Harbor, and the ship left the next day to participate in Operation Enduring Freedom.