Her presence has added to speculation that she could be in line for a leadership position - maybe even the top job itself - in the nuclear-armed country's hereditary dictatorship.
She appeared on Wednesday alongside Kim at a massive military parade, where state media showed her marching with him and her mother, Ri Sol Ju, at the head of military commanders, sharing juice drinks and speaking in each other's ears as they observed the events.
A day earlier, Ri and the daughter were once again with Kim as he wined, dined and flattered military commanders at a lavish banquet commemorating this week's army foundation anniversary.
"For all we know this is just him doting on a favourite child, but the more that she shows up, the more it seems that she's either being fully groomed for leadership or at least floated as a possibility," said Mason Richey, a professor at Hankuk University of Foreign Studies in Seoul.
What is more clear is a message that the country's nuclear weapons are for posterity, and she's a part of that, he added.
"So another way of signalling that denuclearisation is totally off the table," Richey said.
The girl has not been named in state media since she was first shown attending a missile launch with Kim last year, but South Korean intelligence officials believe she is the daughter identified as Ju Ae by former American basketball player Dennis Rodman, who spent time with Kim's family in 2013.
Rachel Minyoung Lee, a North Korea expert with the Vienna-based Open Nuclear Network, said it is premature to conclude that Ju Ae is being prepared for leadership, but agreed that her presence at exclusively military events suggests the main purpose is to underscore the importance of continued weapons development for the security of future generations.
"The North Korean leadership probably has to make the case for why the country has to keep investing in national defence in spite of the deteriorating economic conditions," Lee said. "And no propaganda can be more potent than the leader’s young daughter to convey that message."