He started in the NFL by signing as an undrafted free agent with the Cleveland Browns, and spent the majority of his career with the New York Giants.

O'Hara's career began with the Cleveland Browns, where he played center and guard and after signing as a rookie free agent in 2000.

[4][5] O'Hara re-signed with the Giants in March 2007 keeping him off the free agent market,[6] despite initial concerns about whether a deal was possible.

[7] The Giants' offensive line has been viewed by some as one of the keys to the team's success,[8] which was cemented following Super Bowl XLII[9] and in the leadup thereto,[10][11] but was seen as early as 2005.

He is now a color analyst for NFL Network and ESPN Radio, and a regular fill-in host for Good Morning Football.