[6] Some of his self-taught practice for high school football included running up a steep hill with a backpack full of books on and pushing cars around.

[3] Thomas signed with the New Orleans Saints as an undrafted free agent, on the recommendation of special teams coach Greg McMahon, who had previously been an assistant at Illinois.

[3] He was impressive in preseason games and the Saints ultimately decided to keep him while releasing the running back they had chosen with their fourth round draft pick, Antonio Pittman.

[13] During Week 2, Thomas turned only the second touch from scrimmage of his NFL career into a 24-yard touchdown against the Saints’ longtime rival, the Atlanta Falcons.

[15][16] After once again starting the season buried on the depth chart, a mid-season injury to Reggie Bush gave Pierre Thomas the lead-back opportunity on the NFL's highest scoring offense.

In the NFC Championship Game against the Minnesota Vikings, Thomas contributed 99 yards and two touchdowns in a narrow 31–28 overtime win that sent the Saints to Super Bowl XLIV.

[23] This win marked the first championship in New Orleans Saints history, capping off an impressive 16–3 season and Thomas's career best 1,095 yards from scrimmage.

After totaling 121 yards in the NFC Wildcard Round against the Detroit Lions, Thomas's season ended earlier than expected against the San Francisco 49ers.

The next day, he was fined $7,500 and an additional $5,000 for wearing red and green tape, a violation of the league's uniform policy.

His parents divorced a few years later and Greta moved with her children to Lynwood, Illinois, where she worked for the United States Postal Service.

[43][44][45] In 2013, Thomas was the Saints' team nominee for the Walter Payton NFL Man of the Year Award in acknowledgment of his extensive charitable activities, including his iCan Foundation, which fights childhood obesity.