He played college football for the Assumption Greyhounds and signed with the New Orleans Saints as an undrafted free agent in 2019.

[2] As a senior at Baltimore's Archbishop Curley High School, Harty was named the 2014 Varsity Sports Network Offensive Player of the Year for football.

[5] That same year, Harty led the Friars to the Maryland Interscholastic Athletic Association (MIAA) B Conference Championship and their first undefeated football season in school history, which included a 28–0 shutout victory over traditional MIAA "A" Conference powerhouse Loyola Blakefield, a game in which Harty amassed 206 total yards (140 rushing, 66 receiving) with 2 touchdowns.

Assumption University career highlights: School records: Harty signed with the New Orleans Saints as a rookie undrafted free agent in 2019.

[8][9] After an impressive training camp featuring a 78-yard touchdown return against the New York Jets in the pre-season,[10] Harty made the final cut and was named to the Saints 53-man roster.

[11] Harty made his NFL debut on Monday Night Football as the Saints primary kick returner in the season-opener against the Houston Texans.

In week 18 against the Miami Dolphins, Harty returned a punt 96 yards for a touchdown, sparking a 4th-quarter comeback for the Bills as they would go on to win 21–14 and clinch the AFC East division title.