As a leader.
Chrom takes on numerous leadership roles throughout the course of Fire Emblem: Awakening. These roles being the Captain of the Shepherds Militia, the Commander of the Ylissean Army, and the prince of Ylisse. In each of these roles Chrom is loved and respected by everyone. He treats those who serve him sternly, but fairly, regardless of where they are from, and treats everyone as an equal and with respect. He doesn't care much for formalities, and if they can prove themselves in a fight they will also have his trust, much to the dismay of Frederick, a knight of Ylisse who serves Chrom.
Even as a leader however Chrom can be quite reckless. He is prone to breaking things while training and is always jumping head first into a fight regardless of the consequences. This is especially evident in Chapter 5: The Exalt and the King when he and his elder sister Emmeryn go to meet with Mad King Gangrel of Plegia, in an attempt to parley with him, to free Maribelle who had been captured by Plegia. Although Gangrel is willing to make a trade for her release if Emmeryn gives him the Fire Emblem, Ylisse's royal treasure, things get heated and Gangrel loses his patience, sending brigands to attack Emmeryn. Without hesitation Chrom cuts down one of the brigands, threatening all will suffer the same fate. As a result of his actions war is begun and Chrom realizes he made a mistake.
Chrom: Forgive me, Emm. I acted rashly.
Emmeryn: It's all right, Chrom. King Gangrel is the one at fault here. You were only protecting me.
– Chapter 5: The Exalt and the King
After Emmeryn's death Chrom realizes what Emmeryn was trying to do––that the people of Plegia also desired peace. Although he is distraught by her death he draws strength from his comrades to bring about the peace his sister desired. Since then there had become a change in Chrom, a change that shaped him into a stalwart ruler, rather than a reckless child. In Paralogue 19: Irreconcilable Paths, if Chrom is the one who defeats him, he states that Chrom treads the "Path of Kings"; Chrom rules by winning hearts, unlike Walhart the Conqueror who rules by winning battles. The two of them are great leaders who have taken opposite paths and I think it's part of what makes them both so interesting. It makes sense though. Chrom admits to Walhart that he is much stronger than him, but the reason why he was defeated was because he stands alone. Chrom's strength comes from those around him and is is but a fraction of that strength. Because of this he was able to defeat Walhart.
I believe Chrom's reasoning for taking this path has everything to do with Emmeryn. She was someone he greatly admired and loved. She believed all people desired peace and died believing it. In a support conversation between Chrom and a male Robin the two share an interesting conversation which I think helps explain the kind of person Chrom is. When he is trying to convince Chrom to be more careful, Chrom says that he can't. Even though being out in the open opens him up to danger Chrom is willing to take the risk as it allows him to connect with others and forge bonds. To Chrom the bonds they make are the true strength of an army, and without those bonds they'd be lost.