Lord Kinnock, who was sat with two of his grandchildren among the Fulham fans in the Ernie Clay stand, was made to relocate by security staff.
The reason? He reportedly infuriated many of the home fans with his vociferous celebrations after Cardiff's opening goal.
Kinnock, a lifelong Cardiff fan, was understood to have 'spoiled' the enjoyment of the match for some Fulham supporters before he was moved away from the stand by security staff.
A Fulham spokeswoman said: "Mr Kinnock was located in the home stand on Saturday and caused some angry responses when he and his family celebrated the Cardiff City goal.
"He was relocated in The Putney End, the away Stand, where there were a number of spare seats.
"We would always relocate away fans found in home areas, if seats are available, to ensure that Fulham fans located in home areas enjoy their matchday experience."
Kinnock was swiftly recognised by Fulham supporters in the stand as the drama unfolded.
This guy and family moved from the Fulham section to the Cardiff one - some in the area reckon it is Neil Kinnock pic.twitter.com/4zzKPmbFBQ
— Sean Fay (@Sean_Fay) September 28, 2013
Another fan wrote on a Cardiff supporters' forum: "Pleased to see Mr Kinnock sitting two rows in front of me in the Ernie Clay stand yesterday.
"I am not sure if Neil has as much experience as me of sitting with the home fans but his celebration of our first goal led to him being escorted from the stand."
Cardiff moved above Manchester United into 11th place in the Premier League table with the 2-1 win away from home.
Is it right for football fans to sit with opposing supporters? Were the Fulham fans justified in getting angry in this situation? Post your views below...