"I am overwhelmed with by it," he told Leeds United Television.
"The boss offered it to me on Wednesday when Dominic left, he approached me straight away and he didn't need to offer it to me twice.
"It's a great honour and he told the rest of the players this morning and they are right behind me and I am looking forward to it and am very excited about the job."
Butler follows in the footsteps of Dominic Matteo, Rio Ferdinand, Lucas Radebe, Gary McAllister and Gordon Strachan.
Strachan was skipper when Leeds last won promotion to the top-flight in 1990.
"I shared the duties with Paul Ince at Wolves and at Sunderland when Kevin Ball was there, but this is the biggest job I have had as skipper to get the club back to where they belong.
"I just go along with my own job, I am vocal out there so that helps, and that's what Kevin Blackwell saw in us. He wants leaders out there, but from what I can see he has a team of leaders.
"The players were happy with the choice as well, they all backed me and said they were right behind me.
"It's not just me that will be shouting out there, there's Kelly and Duberry who are very vocal.
"I am my own captain though and I will go about things in my own way and the players will get to know me and find I am fair with it.
"I am the middle man to go from the players back to the gaffer and vice-versa. If they have any problems I am the man who has to face the boss and the board.
"It's added pressure on me but I am going to thrive on it."