Long replaced Keane, who was away signing a new contract extension with LA Galaxy, in Wednesday night's friendly against Serbia, and claimed his 11th Ireland goal in the 2-1 loss at the Aviva.
Keane's 131 appearances for his country have yielded a staggering 62 goals but Long is looking forward to the challenge of replacing the 33-year-old if called upon by Ireland manager Martin O'Neill.
The 27-year-old Hull forward said: "I have been here a long time and I have been biding my time, waiting for my chance to come and learning every time I come into the squad.
"I'm sure if the gaffer sees me as a viable option, I'm ready to take that, I'm ready to jump in.
"Wearing that green jersey is a privilege for anybody, so I'm looking forward to the challenge.
"I am going back to Hull now and I'll try to get the confidence back and keep scoring goals and come here in the summer still a Premier League player."
Long himself has 44 senior caps to his name and O'Neill has hinted he could have a significant role to play in the Euro 2016 qualifying campaign that starts in September.
But with Keane having also committed himself to the quest to reach the finals of another major tournament, Long will have the opportunity to continue to learn from the nation's record international goalscorer.
Long said: "Robbie's record is unbelievable and I don't think it will ever be touched.
"But I can learn from him as well. He's brilliant to have in and around the squad because he talks to us as well in training and helps us out, and he's a really good captain.
"Obviously the gaffer didn't have him here and went with me up front, and hopefully I gave him something to think about."