The Seinfeld actor appeared on the Late Late Show with Craig Ferguson, where he commented that he considers cricket to be a "gay game".
In a Twitter post, Alexander wrote that at first he didn't understand what was wrong with the remark until speaking with gay friends who explained to him its problematic nature.
He wrote: "I would like to say - I now get it. And to the extent that these jokes made anyone feel even more isolated or misunderstood or just plain hurt - please know that was not my intention, at all or ever.
"I hope we will someday live in a society where we are so accepting of each other that we can all laugh at jokes like these and know that there is no malice or diminishment intended."
Alexander went on to admit that as someone with many gay friends he "should know better".
The actor recently filmed a guest spot on Two and a Half Men.
Watch Jason Alexander's appearance on the Late Late Show below: