[2] He holds multiple American and world paralympic swimming records in freestyle, backstroke, butterfly, and individual medleys.

[7][8] Raised in Freehold Township, New Jersey, he began swimming at the age of six at the Ocean County YMCA.

[16] Griswold competed at his first international meet in 2014, and rose to prominence within the S8 classification initially gaining success in the distance freestyle events, winning his first world championships bronze in 2015.

He carried his success into the 2020 Tokyo Paralympic Games by winning the gold medal by 4.27 seconds and breaking the world record.

At the 2022 World Para Swimming Championships,[19] Griswold claimed his third consecutive title in the 100 m backstroke S8.

In September 2020, the United States Center for SafeSport listed Griswold in its disciplinary database as having temporary restrictions for allegations of misconduct (which could cover a range of degrees of physical, emotional or sexual abuse).

[22][5] Egbert, who is intellectually disabled and has autism, and has the mental capacity of a 5-year-old according to court filings, says that he was groomed by Griswold, and threatened with retaliation.