This handout photo taken and released by South Korean newspaper Munhwa Ilbo shows U.S. Ambassador Mark Lippert after he was injured by an armed assailant in Seoul. (Munhwa Ilbo/AFP/Getty Images)

Since arriving in Seoul last year, U.S. Ambassador Mark Lippert has gone to great lengths to be an approachable diplomat, taking various steps to connect with ordinary South Koreans and forgoing the bunkered lifestyle of many top U.S. officials overseas.

Unlike previous ambassadors, Lippert made a point of walking from his official residence to the U.S. Embassy about half a mile away, stopping to greet Koreans along the way. He could often be seen on the streets of central Seoul early in the morning and late at night walking his basset hound, Grigsby.

Lippert and his wife, who enthusiastically chronicled their diplomatic life in a blog called “ Lipperts in Korea ,” even decided to give their first child, regardless of gender, a Korean middle name “as a special part of his or her history here in the Republic of Korea.” James William Sejun Lippert was born in January.

It’s unclear whether the open demeanor that Lippert brought to his high-ranking role made him more vulnerable to an out-of-the-blue knife attack that left him recovering in the hospital on Thursday. The assailant, who came at the diplomat with a ­10-inch knife during an event at a Seoul arts center, was described as an opponent of U.S. military involvement in South Korea with a history of violent assault. Seoul police said early Friday that they plan to charge the attacker, Kim Ki-jong, with attempted murder.

North Korea, through its state-run news agency, called the attack “deserved punishment” for U.S. participation in military exercises on the Korean Peninsula.

Editor’s Note: This video contains graphic content. Mark Lippert, U.S. ambassador to South Korea, was slashed in the face and hand by a Korean nationalist, police said. (Reuters)

Lippert, who had a security detail with him at the time of the attack, said he was in good spirits after receiving 80 stitches to the wound to his face. “Doing well and in great spirits,” Lippert tweeted from the hospital.

The attack took place as debate continues about the correct balance between keeping U.S. diplomats safe and allowing them to interact freely in the countries where they serve. That debate has intensified since the 2012 attacks on U.S. facilities in Benghazi, Libya, that left U.S. Ambassador J. Christopher Stevens and three other Americans dead.

Ronald Neumann, the president of the American Academy of Diplomacy, said the pendulum had swung too far toward eliminating risk for U.S. officials, making it difficult for them to get out and develop firsthand knowledge of the countries where they’re posted.

“You can’t secure everybody against everything,” said Neumann, a former U.S. ambassador to Afghanistan, Algeria and Bahrain.

Yonhap News Agency quoted South Korean police officials as saying the U.S. Embassy in Seoul had not requested a security escort at Thursday’s event. After the attack, South Korean police said they would enhance security around U.S.-related facilities and personnel, providing Lippert with four police guards, and his wife with three.

The assault came not long after Lippert took up the position in Seoul, which culminated more than a decade of work as a policy staffer and Washington insider.

Lippert, 42 and a native of Ohio, had made his way into politics as an aide to Sen. Patrick J. Leahy (D-Vt.) and to former senator Thomas A. Daschle. In 2005, he joined the office of then-Sen. ­Barack Obama.

South Korean protesters shout slogans Thursday as they hold the photos of North Korean leader Kim Jong Un, center and right, the late leaders Kim Jong Il, second from left, and Kim Il Sung, left, during a rally denouncing the attack on U.S. Ambassador Mark Lippert in Seoul. (Lee Jin-Man/AP)

Lippert, who earned a master’s degree in international policy studies at Stanford University and studied Mandarin in Beijing, proved a valuable adviser to Obama, who was trying to get up to speed on foreign affairs. He later advised Obama’s 2008 campaign.

A Navy reservist, Lippert returned to active duty from 2007 to 2008 and served as an intelligence officer in Iraq. When he left the campaign, Lippert helped recruit Denis McDonough, a former Hill colleague, to replace him. McDonough is now the White House chief of staff.

When President Obama took office, he installed Lippert and McDonough in high-level positions at the National Security Council, where the youthful ­political appointees reportedly clashed with the national security adviser at the time, Gen. James L. Jones, according to an account in Bob Woodward’s “Obama Wars.” Jones considered them “major obstacles to developing and deciding on coherent national security policy,” Woodward wrote, and he accused Lippert of leaking unflattering information about him to the press.

Derek Chollet, a former senior Pentagon official who is a longtime friend of Lippert’s, said reports of White House drama were “probably more perception” than reality.

He added: “Mark is an intense guy. He moves fast, thinks fast, works it very hard, is up at all hours. He’s relentless, and that’s why he’s so good.”

Obama later nominated Lippert as assistant secretary of defense for Asia. His confirmation hearing was combative, as Sen. John McCain (R-Ariz.) aggressively questioned Lippert’s opposition to the U.S. military surge in Iraq and his alleged undermining of Jones.

McCain “had to be convinced that Lippert was not just an empty suit,” said Frank Jannuzi, who served as the Asian affairs director for the Senate Foreign Relations Committee. “The good news is that Lippert is not just a quick study but a smart guy.”

Ultimately, Lippert was confirmed and was later selected as chief of staff to then-Defense Secretary Chuck Hagel.

A senior defense official, speaking on the condition of anonymity to discuss a former colleague, said that Lippert was known for his inclusive style as chief of staff, encouraging a range of officials to attend meetings and present their views to Hagel — not the norm in Washington.

Lippert’s arrival in Seoul came as the Obama administration tries to shift its foreign policy toward greater engagement with Asia. Although he did not have the star power of a Caroline Kennedy, the ambassador to Japan, Lippert’s arrival in South Korea made sense because “having somebody close personally to the president sent a message to South Korea that the pivot to Asia was important,” said a former colleague of Lippert’s who was not authorized to speak on the record in his current job.

South Koreans, who count the United States as their closest ally, reacted in horror to the attack on Thursday.

President Park Geun-hye, who had her own face slashed while campaigning in 2006, said the incident was “not only a physical attack on the U.S. ambassador in South Korea but also an attack on the Korea-U.S. alliance.” Both Obama and Park called Lippert after the attack.

“What the world has seen in Mark’s doggedness and fearlessness during the last day, the President has seen up close since he first arrived in the Senate,” McDonough said in a statement. “Ambassador Lippert is smart, tough, and committed to his mission, whether that was in the Senate, on the campaign, at the White House, in the Pentagon and overseas in uniform or as our Ambassador.”

Jannuzi, who is currently president of the Mansfield Foundation, said that Lippert’s openness had been a hallmark of his tenure so far and that he hoped officials would not “create a bubble around him” as a result of the attack.

“Diplomats are at their best when they are out of the office meeting with people,” he said.

Anna Fifield reported from Singapore.