Born in Milwaukee, Wisconsin, Greer moved to Texas at age seven and later lived in Jackson, Tennessee, where he attended South Side High School.

[6] Greer's scouting report noted that he lacked size, a factor that might pose "problems in handling the larger receivers.

He was injured on November 8, 2009, and missed most of the rest of the 2009 regular season, but returned in time to play a significant role in the playoffs.

[9] On February 12, 2014, three months after tearing his left ACL against the 49ers, Greer was cut by the New Orleans Saints to create more cap space for the team.

He has established a non-profit foundation, the Greer Campaign, focused on programs to assist both single and married fathers in developing their parenting skills.