Gilbert was born in Fort Lauderdale, Florida. He attended St. Thomas Aquinas High School in Fort Lauderdale, and was a standout lineman for the St. Thomas Aquinas Raiders high school football team. He was also a member of the Raiders basketball team and threw the shot put and discus for the Raiders track and field team.
Gilbert attended the University of Florida, where he played coach Urban Meyer's Florida Gators football team from 2006 to 2010. As a true freshman in 2006, he was redshirted. He made his first career start for the Florida Gators in a game against Florida Atlantic in 2007 at right guard in place of the injured Maurkice Pouncey. During the Gators 2008 BCS National Championship season, Gilbert started two games at left guard against Hawaii and Miami. He started in all 14 games for the Gators at right tackle in 2009, and earned SEC Offensive Lineman of the Week honors for his performance against Kentucky on September 26. In 2010, Gilbert started in all 13 games, playing both tackle positions. During his college career, he appeared in fifty-two games and started thirty of them.
Gilbert was drafted 63rd overall in the 2011 NFL Draft by the Pittsburgh Steelers. He is the first Florida player at his position to be drafted since Max Starks was a third-round selection by Pittsburgh in 2004. Gilbert joined former Florida center Maurkice Pouncey, who was drafted in the first round (18th overall pick) by the Steelers the year before. Gilbert's first NFL start was on September 18, 2011 when the Steelers played the Seattle Seahawks. Gilbert filled in for the Injured Willie Colon. On December 29, Gilbert was named the Steelers 2011 Rookie of the year after starting 13 games inplace of the injured Colon. On November 26, 2012, Gilbert was placed on injured reserve after suffering an ankle injury in Week 6.
On August 19, 2014, Gilbert signed a five-year, $30 million contract extension with the Steelers.