Born 1943 in Beersheva, in what was then British-ruled Palestine, his family was uprooted and fled to the Gaza Strip with the founding of Israel in 1948.
After studies in Alexandria, Egypt and London, Sarraj returned in 1977 to open a psychiatric practice in Gaza.
Through his work, he became known for documenting the affects of conflict on children in the coastal Palestinian territory.
In an interview with AFP in the early 2000s, Sarraj said the children most traumatised by war were those who had lost their mothers or their homes -- "Mothers because they symbolise the endurance of love; homes because they symbolise the endurance of security."
But it was primarily his efforts for peace with Israel and a non-violent resolution of the decades-old conflict that gained him international attention.
When the second Palestinian intifada, or uprising, against Israel broke out in 2000, Sarraj urged Palestinians to embrace the non-violent approach of India's Mahatma Gandhi and America's Martin Luther King Jr.
He had agreed to an interview with AFP the day after the December 5 death of another champion of reconciliation, Nelson Mandela, but his doctors said he was too weak.
Dr Ruchama Marton, an Israeli psychiatrist who said a meeting with Sarraj in 1988 inspired her to found what became Physicians for Human Rights-Israel, described him as a wise, noble and tactful man.
"He was an understanding person and possessed non-violence that cannot be learned but simply came from him. He objected to violence in a non-violent way, without being submissive."
Despite his having spent time in both Israeli and Palestinian jails, "he was a man who neither internalised nor used anger or bitterness," she said.
And although he was a refugee, "he didn't see himself as one, rather a Gazan. The irony is that he was born in Israel and died in Israel."
"We were truly on the same side, the side of people who don't want a violent solution to a problematic situation, who are fully devoted to human rights, not as a slogan but as a way of life all day, every day," she said.
Gaza's Islamist Hamas rulers paid tribute to Sarraj, calling him "the great Palestinian rights activist... dedicated to the service of the Palestinian people, to resistance to the Zionist occupation and to all forms of racism."
The Palestine Liberation Organisation praised him as "a great activist who left a deep imprint on the Palestinian struggle."
Sarraj received numerous awards, including the Olof Palme Prize in 2010 for having "revealed the destructive influence of repression on mental health."
"It is not me but the victims of violence, torture and war who are the real heroes," he told AFP in Gaza at the time.
He was also active in trying to promote rapprochement between Hamas and Palestinian president Mahmud Abbas's Fatah movement, chairing a reconciliation committee seeking to heal the six-year breach between the two, so far without success.
Sarraj was buried on Wednesday after a funeral service at Gaza's Al-Omari mosque.