The designated hitter's full-count blast off Rays rookie Jeff Niemann tied him with Mel Ott for 21st in Major League History.
"It's very humbling when you hear your name with those greats [such as Ott]," Thome said. "It's really a cool thing."
Thome's three-run homer was hit so far into right field that it reached the "C-ring," the second catwalk from the field. It is the first fair ball to reach that part of the stadium this season.
"That home run that Thome hit might have been the longest one I've seen at this ballpark," Rays manager Joe Maddon said. "Tried to throw him a fastball and it kind of cut to a bad spot."
White Sox manager Ozzie Guillen was equally amazed, saying it was the longest ball he had ever seen anyone hit.
"If that ball didn't hit the catwalk, it would have hit the walls out there [behind the scoreboard]," he said.
Thome's blast traveled 418 feet and scored Juan Uribe and Nick Swisher to put the Sox ahead, 3-0.
As for if it was the farthest hit he's seen, Thome was modest: "That [homer] is right up there," he said. "It felt pretty good."
Thome is now just one home run away from tying Ernie Banks and Eddie Mathews for 19th place all-time. He nearly eclipsed that mark in his fifth at-bat, but was several feet shy of the center-field fence.
The home run caps off a whirlwind week for Thome, who served a one-game suspension on April 15 for his actions in the game vs. Detroit on April 11. The designated hitter also drew a pair of walks on April 17 to move past Willie Mays into 18th place all-time with 1,456.
Thome recorded another two walks on Friday, bringing his total to 1,458. Hall of Famer Eddie Collins sits in 17th place with 1,499.
Brittany Ghiroli is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.