Lippert has been hospitalised since Thursday at Seoul's Severance Hospital, where President Park Geun-hye also received treatment in 2006 when she was knifed by a man with a box cutter during an election rally. Park was then an opposition party leader.
Park's office said the president went to the hospital shortly after she returned to South Korea yesterday from a Middle East tour.
Park was quoted as saying "my heart ached more" because Lippert is hospitalised at the same hospital due to a similar attack. Lippert told Park that he and his wife have been moved by the support the South Korean government and people have showed to him, according to a statement from the presidential Blue House.
In Washington, State Department spokeswoman Jen Psaki said Lippert is "active and in good spirits." She said the outpouring of support and Park's visit to the ambassador "speaks to the strength and vitality" of the US-South Korean relationship.
The alleged attacker, known as an anti-US activist who was previously convicted of hurling a piece of concrete at the Japanese ambassador in Seoul in 2010, was arrested Friday. Kim Ki-jong could face charges including attempted murder.