[1] He speaks of having a joyful, though financially modest, childhood, with at least one brother, and he keeps in contact with his father, who is an amateur painter and engineer working in Croatian Railways in Zagreb.

When the Croatian War of Independence (1991–1995) breaks out, Luka is living in Vukovar and is at first hesitant to move away, as he wants to finish his internship.

[2] He moves to the United States of America some time after that for a fresh start, but evidence he suffered from both survivor's guilt and PTSD soon emerge, largely in terms of his personal relationships.

[1] Although initially reluctant to settle in one place, preferring to travel between Chicago and an unnamed southern city in his boat, a job offer from Kerry Weaver leads him to take a permanent position at County General.

Soon after arriving at County General he became interested in the then-pregnant Head Nurse Carol Hathaway, although their relationship was largely as friends.

While involved with Carol, Luka met and began teaching medical student Nurse Abby Lockhart, who would eventually become the longest and most important relationship in his new life.

Luka recognized the potential to be a good doctor in her, and began to mentor and encourage her when her personal life led to her withdrawal from medical school.

Early into Season 7, Luka became involved with Abby, now an ER nurse, after a spontaneous kiss led him to reconsider his relationship with her.

An encounter with a dying bishop provided Luka with a measure of absolution for the death of his wife, and for a time, he seemed ready to move forward.

He rebuffed a series of advances by medical student Erin Harkins (Leslie Bibb) before making a drunken pass after a painful encounter with Abby.

Despite his depression, he was able to save a boy's life using an unorthodox method, and was allowed to stay on condition he undergo counseling, with which he was minimally cooperative.

When Carter returned to the United States, Luka stayed behind, working at a rural clinic in the Congo, until he contracted malaria.

[3] Though the rebels at first objected and pointed their guns at him, their leader noticed a small cross hanging around Luka's neck, given to him by the mother of a young patient.

On his return from Africa, Luka began a relationship with Nurse Samantha Taggart, and for about a year and a half all seemed fairly well until he expressed his desire to have more children.

While treating Bishop Lionel Stewart (portrayed by James Cromwell), he seemed to come to terms with his bitterness, although he still wrestles with what God is and isn't responsible for.

Following the departure of Dr Susan Lewis, Luka was made Chief of Emergency Medicine in Season 12, by an initially reluctant Kerry Weaver.

Nonetheless, Clemente's personal issues (including being suspected of shooting his girlfriend, and insomnia developed from being stalked by her ex-husband) forced Luka to admit him for PTSD near the end of Season 12 and fire him.

Ultimately, Kerry resigned anyway about halfway through the season and sought a new career in Florida, parting on good terms with Luka.

In "Twenty-One Guns", the season 12 finale, Kovač is injected with a paralytic medication during an escape attempt by Sam's jailed ex-husband.

In the season 13 premiere, "Bloodline", Kovač was rescued by Weaver, only to learn that Abby sustained possibly serious injuries as a result of the shootout.

After several tense weeks and emergency surgery, a healthy Joe was released from the hospital, and Luka and Abby settled into parenthood.

Soon after returning to work, Luka had to defend himself in a malpractice suit brought by Curtis Ames (played by Forest Whitaker), a carpenter who suffered a debilitating stroke while under Kovač's care for pneumonia.

The situation came to a climax when Ames took Luka hostage, subjected him to a night of mental and physical torture (by crushing Kovač's hand in a vise), and shot himself to death, on a rooftop, in front of the horrified doctor, as police surrounded them.