Even with all of his success, however, Harrison is often criticized because he has not yet won a championship, and criticized especially about his performences in big playoff games, stating that he often seems to "disappear." Harrison, however, was involved in one of the most infamous blunders in the history of the NFL playoffs. In the 2003 NFL playoffs, Harrison, against the Denver Broncos, caught a 20 yard pass from Peyton Manning across the middle. Then, Deltha O'Neal, the Broncos cornerback, had forgot to touch Harrison to down him, Harrison proceeded to stand up and continued running, eventually scoring on a fifty-yard touchdown play. Broncos Head Coach Mike Shanahan was infuriated with O'Neal and the rest of the Bronco defenders that were around Harrison, who helped clinch victory as the Colts went up 28-3. Indianapolis would eventually win 41-10 in a total blowout.

Harrison would finish that game against Denver with 7 receptions for 133 yards and 2 touchdowns, in his finest post-season performence to date. Against the Chiefs he had another solid post-season game against the Chiefs, gaining 98 yards on 6 catches. Just when Harrison looked like he had rid himself of his post-season jitters, he was played aggressively by New England Patriots cornerback Ty Law in the 2005 AFC Title game, who limited him to just 3 catches for 19 yards. This game, however, was debated by many fans, who claimed that there had been an excessive amount of pass interference that was not called. The NFL reviewed this game and agreed that the game had been officiated poorly. This led to rule changes in the following off-season, which limited cornerback's actions against receivers. Many feel these rule changes have now made it so there can no longer be a "shut down corner" in the present NFL anymore. Despite this, the Colts would still end up losing to the Patriots in a divisional playoff game the following year, in which Harrison had 5 receptions for 44 yards (it should be noted that Ty Law was injured for the rest of the season prior to this game, and Asante Samuel was covering Harrison in the Colts' defeat).

While his post-season performences have not been stellar, no one can overlook Harrison's regular season career, where his statistics are clearly capable of securing his entry into the NFL Hall of Fame.

In a recent episode of "You Can't Blame" on ESPN Classic about the excessive celebrations of wide receiver Terrell Owens, former Buffalo Bills coach Marv Levy said this about Harrison: "Terrell Owens is a guy that has to go out there and get recognized for his antics and celebrations. While a guy like Marvin Harrison wants to be recognized for his play on the field, not his antics or celebrations. That's the kind of receiver you want on your team".