As junior, Pittman was named honorable mention All-Pac-12 Conference after posting 41 receptions for 758 yards with six touchdowns. Following the end of the season, Pittman considered forgoing his final season of eligibility to enter the 2018 NFL Draft but opted to return for his senior year after receiving a third-round grade from the NFL Draft Advisory Board. Pittman caught 10 passes for 232 yards (5th-most in a game in USC history) and a touchdown in a 30–23 win over tenth-ranked Utah on September 20, 2019. Pittman finished the season with 101 receptions for 1,275 yards and 11 touchdowns and was named first team All-Pac-12 and a consensus second team All-America selection. He was also a finalist for the Fred Biletnikoff Award and won the Pop Warner Award, given to the college senior with the biggest impact on and off the field.

Pittman was selected by the Indianapolis Colts in the second round with the 34th overall pick in the 2020 NFL Draft. Pittman made his professional debut on September 13, 2020 against the Jacksonville Jaguars, catching two passes for ten yards in the 27–20 loss. He was placed on injured reserve on October 3, 2020, due to compartment syndrome in his calf. He was activated on October 31. He had his first 100-yard game with seven receptions for 101 yards in the 34–17 victory against the Tennessee Titans in Week 10. He was the first Colts’ rookie to have 100 receiving yards in a game since Donte Moncrief in 2014.

Pittman is the son of former NFL running back and Super Bowl champion Michael Pittman and Kristin Randall. Pittman Sr. played on the Tampa Bay Buccaneers 2002 championship roster. His younger brother, Mycah Pittman, plays wide receiver for the Oregon Ducks. Pittman also runs a YouTube channel with his fiancé, Kianna Galli. The channel is called “Michael and Kianna”. They were engaged on October 22, 2020.