Who is Lord Commander Mormont from A Clash of Kings and what is their importance?

Lord Commander Mormont is the head of the Night's Watch. He is the father of Ser Jorah Mormont. He tells Jon Snow the story behind Maester Aemon's joining the Night's Watch. Aemon joined the Night's Watch so that he couldn't be used as a rival heir for his brother's throne. Mormont tells Jon of the brothers' history, since Jon is the brother of Robb Stark, a claimant to the throne. Mormont goes with the party to the Fist of the First Men. The Watch is looking for signs of the wildings, who have fled their villages. Mormont sents Jon out with a scouting party to find out where the wildings went.