World leaders sent congratulatory messages to Park, the chairwoman of the conservative Grand National Party who this week became South Korean's the first female president-elect.
After winning 51.6 percent of the vote, Park takes charge amid heightened tensions on the Korean Peninsula. Speculation has circulated over the direction of the North Korean regime more than a year after longtime leader Kim Jong Il died, leaving control to his son Kim Jong Un.
Park said she'd steer a government that would promote regional peace and reconciliation. She said Thursday security concerns over North Korea, however, were serious.
"North Korea's long-range missile launch symbolically showed how grave the security reality we face is," she was quoted by South Korea's Yonhap news agency as saying.
There's been no formal response from the North Korean government on Park's election. Yang Moo-jin, a professor at the University of North Korean Studies in Seoul, told Yonhap that Pyongyang was likely taking a wait-and-see approach.
"Rather than attacking Park, it looks like North Korea will first explore her policies on the North," he said.
North Korea's rocket launch last week was expected to coincide with the death of Kim Jong Il and South Korean presidential elections. Both countries remain technically at war.