Though LG did not elaborate on its forecasts, analysts say LG's mobile business likely turned an operating loss for the eighth-straight quarter.
The hefty profits highlight Samsung's resilience after the embarrassing recall of its fire-prone Note 7 smartphone past year.
Jay Y. Lee, the 48-year-old boss of Samsung Group [SAGR.UL], is on trial on charges including bribery and embezzlement in a scandal that led to the ouster of President Park Geun-hye.
On Friday, Samsung Electronics, the world's largest manufacturer of smartphones, announced its estimated operating profit for the January-March quarter on Monday.
Revenue for the quarter rose 0.4 percent to 50 trillion won, compared with analysts' forecast of 49.4 trillion won.
The operating profit is the firm's second-highest for a quarter and a rise of 48.2 percent compared to a year earlier.
Trump says missile strikes against Syria in USA "vital interest"
President Donald Trump speaks at Mar-a-Lago in Palm Beach, Florida , after the USA fired a barrage of cruise missiles into Syria. Washington has blamed Assad's forces for the attack that killed scores of people in rebel-held Khan Sheikhoun on Tuesday.
Lee Jae-Yong, the vice-chairman of Samsung Electronics, was brought into the Seoul Central District Court bound and handcuffed.
Lee's defence lawyers however said the payments to the Choi were charitable contributions for sports and culture development that Samsung was obliged to make under pressure from officials, and not bribes.
"Generally speaking I think the improved product mix in appliances and televisions and the company's efforts to sell high-end products lifted profits", HI Investment analyst Song Eun-jeong said. Samsung gave or promised to give 43.3 billion won ($38 million) to four entities controlled by Park's friend Choi Soon-sil, who has been charged with misuse of power and meddling in state affairs.
All this is happening amid management upheaval at South Korea's biggest family-run conglomerate, with third-generation leader Lee embroiled in a scandal that has already led to Park's removal from office for allegedly receiving bribes.
Samsung's latest flagship phone, the Galaxy S8, didn't debut until after the end of the quarter and isn't reflected in the figures. They said Samsung's semiconductor division likely recorded profit much higher than expected, contributing more than half of the company's quarterly income as supplies of memory chips remained tight while demand from global smartphone makers was solid. The S8 was its first major smartphone launch since the fire-prone Galaxy Note 7 fiasco.