He is the captain[4][5] of Assam in domestic cricket and plays for Rajasthan Royals in the Indian Premier League (IPL).

Parag Das and former captain of team India MS Dhoni featured in Railways' tournaments together in Kharagpur and Guwahati.

[7][8][9] His mother, Mithoo Barooah, is a former national record-holding swimmer in 50m freestyle who represented India at the Asian Championships and SAF Games.

1985 was a momentous year for Mithoo as she bagged a Silver medal (this was an unprecedented milestone by any male or female swimmer from Assam) in the 50 metres breast stroke in the Asian Age group championship.

[11][12] As a 14-year-old, Riyan Parag could have been the youngest first-class debutant in India, but for the Assam selectors, who were not on the same page as the state's then coach Sanath Kumar.

Coming in to bat at number four, he notched blistering centuries against Rajasthan, Jammu and Kashmir and Sikkim, and an unbeaten fifty against Vidarbha.

[21] In the quarter finals of the tournament chasing a mammoth 351 against Jammu and Kashmir, he scored 174 off 116 balls, an innings that was studded with a dozen sixes and an equal number of fours.

[22][23] In one of the group stage matches of the first-class 2022-23 Ranji Trophy tournament playing against Hyderabad, Riyan struck 78 off 28 balls with the bat in the 2nd innings apart from picking up an eight wicket match-haul with his leg break bowling to help his team clinch a closely fought contest by 18 runs.

[31] His record-breaking seven consecutive half-centuries came against Bengal,[32][33] Chandigarh, Himachal Pradesh, Bihar, Services, Sikkim and Kerala.

In the same season, Riyan Parag struck consecutive first-class centuries against Chhattisgarh and Kerala and a 75 against Andhra Pradesh.

His twin fifties in the first-game - including a 33-ball half-century, the second-fastest behind Virat Kohli in recorded youth Tests, helped India set up a declaration and paved way for a 334-run victory in Chesterfield.

In the second Test, he made a half-century in India's quest for quick runs, strung a 131-run stand with Shubman Gill for the fourth wicket and set up a 2–0 series win.

Prior to the tour, he finished a bumper season, in which he was the second-highest run-getter in the 2016-17 Cooch Behar Trophy, India's national four-day tournament for U-19 players, with 642 runs in 14 innings and a best of 202 not out.

[13] In December 2018, he was bought by the Rajasthan Royals in the player auction for the 2019 Indian Premier League at his base price of 20 lakhs.

[61] In the third T20I of the Series, he scored a quickfire 18 ball 26 from the lower-middle order, stitching a vital 54 run sixth wicket partnership with Shubman Gill after a mini-collapse.