McKinney then went to play for Texas A&M University and saw action as reserve defensive end as freshman and accumulated three tackles. He started the final eight games of sophomore season at left guard. As a junior, McKinney started at left guard the entire season and earned second-team All-Big 12 honors as the offense averaged 404.5 yards per game. He started 12 games as a senior season at left guard and earned first-team All-Big 12 honors and helped the offense average 205.4 yards per game rushing. He was a four-year letterman and three-year starter for the Aggies, and started the final 32 games of his career at left guard. In 2015, McKinney was voted onto the Texas A&M Top 100 Football Players of All-Time list.
Professional career
Indianapolis Colts
McKinney was drafted in the 1998NFL Draft by the Indianapolis Colts. In 1998, he started all 16 games at left guard and was one of only four NFL rookieoffensive linemen to start each game at only guard. He was the fourth guard in Colts history to earn all-rookie honors and was a member of a line that allowed 22 sacks, second-lowest total in the NFL. In 1999, he started 14 games at left guard and missed the first snap of his career when he was inactive at Philadelphia. He was inactive for two more games after an emergency appendectomy. In the 2000 and 2001 McKinney started a total of 30 games for the Colts.
He then left the Colts as a free agent during the 2002 NFL Season. He was the first unrestricted free agent to be signed by the Houston Texans. He started all 16 games at center and handled every offensive snap. In 2003 he started all 16 games at center for the second consecutive season and joined Chester Pitts as the only two Texans offensive linemen to start all 32 games in the club’s brief history. He then started all 32 games for the 2004 and 2005 seasons for the Texans. On September 23, 2007, McKinney suffered a torn ACL in a loss to the Colts. He was placed on injured reserve, ending his season. He was released the following offseason.
On May 18, 2008, McKinney was signed by the Miami Dolphins. His younger brother, Seth McKinney, was drafted by and played for the Dolphins from 2002 to 2006. The team released McKinney on August 18.
McKinney was signed by the Seattle Seahawks on December 5, 2008 after guard Mike Wahle was placed on injured reserve.
Other ventures
McKinney was a minority owner of the Freebirds World Burrito chain from 2003-2007 before the company was sold to a larger conglomerate. McKinney also operated Velocity Sports Performance training centers in the Houston area from 2004-2008. In 2007 McKinney began his own hunting and whitetail deer breeding operation called McKinney Whitetails, in Marquez, TX near his hometown of Centerville, TX. McKinney owns McDonald's restaurants in Hosuton, TX