Hishamuddin is a senior figure within the United Malays National Organisation (UMNO), Malaysia's largest political party and the leading member of the Barisan Nasional coalition that governs the country. He is one of the party's three vice-presidents and was the chief of the party's youth wing from 1998 to 2009.
He is the son of Malaysia's third prime minister, Hussein Onn, and the cousin of the sixth and current prime minister, Najib Razak.
Hishammuddin was born on 5 August 1961, the fourth child and the eldest son of Hussein Onn, who became the third Prime Minister of Malaysia, and Suhaila Noah. He is the grandson of Onn Jaafar, a prominent Malay leader and the founder of UMNO, whose mother was a Circassian from Turkey.
He attended the Malay College Kuala Kangsar before his father became Deputy Prime Minister in 1973. Upon his father's appointment to the post, he attended St. John's Institution, and then the Alice Smith School, in Kuala Lumpur, before attending the English public school Cheltenham College.
He graduated with a Bachelor of Laws (LL.B) degree from the University of Wales, Aberystwyth, in 1984. He also attended the London School of Economics and received a Master of Laws (LL.M) degree in Commercial and Corporate Law in 1988.
Before entering politics, he was a lawyer with a large Malaysian firm then known as Skrine & Co. (now known as Skrine) and later, a Kuala Lumpur firm then known as Lee Hishammuddin (now Lee Hishammuddin Allen & Gledhill).
His wife, Marsilla Tengku Abdullah, is a princess from the state of Pahang. They married in 1986.
Upon returning from the United Kingdom in 1989, Hishammuddin joined UMNO. He rose through the ranks of UMNO's youth wing in the 1990s, becoming its national chief in 1998. He assumed the position at a time when UMNO Youth had been torn apart by the sacking of the Deputy Prime Minister Anwar Ibrahim, who was popular among young UMNO members. Hishammudin's predecessor, Ahmad Zahid Hamidi, had been an Anwar supporter.
Meanwhile, in 1995, he had been elected to the federal parliament for the Johor-based seat of Tenggara. He was immediately appointed as Parliamentary Secretary for International Trade and Industry in the government of Mahathir Mohamad. His rise to the leadership of UMNO Youth in 1998 coincided with his elevation to the full ministry the following year, as the Minister for Youth and Sport. He retained his parliamentary seat in the 1999 election.
In 2004, the Barisan Nasional government, now led by Abdullah Badawi, was returned to power with Hishammuddin holding the newly created seat of Sembrong. Hishammuddin was re-elected as the leader of UMNO Youth and appointed Minister for Education. In his second term as UMNO Youth's leader, Hishammuddin waded into controversy by brandishing the keris, a Malay sword and symbol of Malay nationalism, at UMNO's 2005 annual general meeting. In response to concerns over the racial rhetoric, then Vice-President Tan Sri Muhyiddin Yassin said that "Although some sides were a bit extreme [this year], it is quite normal to voice feelings during the assembly." The racially provocative act was criticised by opposition politicians as well as some Chinese politicians from the Barisan Nasional coalition. In 2008, Hishammuddin conceded that the act had caused the coalition to lose support among non-Malay voters in that year's general election.
In 2009, the resignation of Abdullah Badawi as prime minister caused a shake-up in UMNO's senior leadership. Najib Razak, Hishammuddin's cousin, became UMNO's president and the prime minister, Muhyiddin Yassin became Najib's deputy in both the party and the government, and the three UMNO vice-presidencies were up for election. Hishammuddin, vacating the leadership of UMNO Youth, contested the vice-presidencies, finishing in second place in an eight-man field. His ascension to the party's vice-presidency in turn guaranteed him a senior Cabinet post, and he was appointed as Minister for Home Affairs. In that position he played a key role in Malaysia's response to the 2013 Lahad Datu standoff in 2013 by militants from the Philippines.
After the 2013 election, in which Najib's government suffered further losses, especially among Chinese voters, Hishammuddin recontested the UMNO vice-presidency. He was barely re-elected in third place, finishing nine votes ahead of Mukhriz Mahathir. He switched ministries with Zahid, taking over the latter's portfolio of Defence. He also assumed the transport ministry on an acting basis; that ministry was normally reserved for the Malaysian Chinese Association, which had decided to withdraw from the Cabinet temporarily, having endured significant losses in the general election. As acting transport minister he was thrust into the international spotlight as the minister responsible for the investigation into the disappearance of Malaysia Airlines Flight 370. The Sydney Morning Herald criticised Hishammuddin in this position, arguing that he had "struggled during daily press briefings to defend his country’s handling of the search and investigation". Najib, however, defended Hishammuddin's performance. His role ceased in June 2014, when Liow Tiong Lai assumed the ministry. Hishammuddin retained his substantive post as defence minister.