"I never heard if they finished or not, but you know, it really inspired me," the St. Marys, Ont., resident said Tuesday, when recalling the adventure on CBC Radio's Afternoon Drive.
"I was like: 'I gotta do this, it's gotta be a bucket list item, gotta do it before I die."
His 14-year-old son, Josh, wasn't immediately convinced that it was worth it.
When his dad told him about his plan, Josh said he told him he'd think about it — which he did, for a couple of days.
"I'm like, you know what? This sounds like it's going to be a lot of fun. What the heck, let's go out and do it," he told Afternoon Drive.
The father and son, along with Derek's brother, set out last month.
"He was in for sure," said Derek, describing his brother's interest in the challenge. "We do a lot of adventurous things together and he was right along with us."
They left St. Marys at 4 a.m., before getting into Lake Ontario at Hamilton's Confederation Park at 6 a.m.
"We were the only ones on the beach, that's for sure," said Derek. "But the water was warm."
Next was a drive to Port Dover, where they took a dip in Lake Erie.
After that, the trio crossed the border in Sarnia, Ont., and ended up in Linwood, Mich., where they got into Lake Huron. The clock was at 1:27 p.m. when they made that entry into the lake.
Derek said they next went to Petoskey, Mich., where they jumped into Lake Michigan.
To complete the set, they then had to get themselves to Lake Superior, which they did shortly after 7 p.m. that night.
They only spent between 30 seconds and one minute in each lake that they hit over the course of the 15-hour journey that Derek said totalled some 1,001 kilometres.
"The goal was to make it in every Great Lake in one day, so we just, we made sure we dunked our whole bodies — our heads and everything were under the water — but we had to get back in that car and continue because failure was not an option," he said.
The Atchisons said their next goal is to swim in two oceans in the same day.
"We're still thinking about it, we're not 100 per cent sure yet," Josh said.