Results dipped below an 11.05 trillion won net profit recorded for the same period a year ago.
The company said the operating profit from the mobile element of the business showed the steepest decline rate since Q1 of 2017.
Samsung posted 58.48 trillion won ($52.2 billion) in consolidated quarterly sales, down 4 percent from a year earlier, and 14.87 trillion won in quarterly operating profit, up 6 percent over the same period.
Samsung Electronics (OTC:SSNLF) published its Q2 2018 results on Tuesday, reporting a mixed set of numbers as headwinds in its smartphone business offset a robust performance by its memory operations. As such, the company say it "will be offering the Note 9 at reasonable prices in order to maximize sales".
Samsung, meanwhile, is said to be prepping a better foldable handset than competitors.
Amid the sluggish premium smartphone market and intensifying competition, Samsung's smartphone shipments and revenue declined QoQ due to the slow sales of Galaxy S9 and S9+ as well as the phasing out of older low-end models.
The company said it also plans to expand the scope of services powered by artificial-intelligence technology, and seek to improve connectivity with voice-recognition system Bixby and mobile payment tool Samsung Pay.
Looking to the second half, the TV market is projected to grow YoY, especially in developed economies, said the company.
Adding to its troubles, its vice-chairman Lee Jae-yong, scion of Samsung's founding family, was jailed previous year for his part in the sprawling corruption scandal that brought down former president Park Geun-hye.
The IT & Mobile Communications (IM) division, which makes smartphones, posted an operating profit of 2.67 trillion won (2.39 billion US dollars) on revenue of 24 trillion won (21.5 billion USA dollars).
For the first half of 2018, Samsung invested 13.3 trillion won in chips and 1.9 trillion won in displays, rolling out a combined 16.6 trillion won in facilities investment.