Jennen began studying the violin at the age of six under the Suzuki Method.
From an early age, Jennen competed in local violin competitions and later won national and international competitions. By his early twenties, Jennen had won over $50,000 in awards and competition prize money.
Jennen studied at Camberwell Grammar School from 1994 to 2001 on a full scholarship and at the Australian National Academy of Music from 2002 to 2005, also on a full scholarship. He then completed a Master of Music Studies degree at the University of Tasmania in one year. Jennen’s teachers included Alice Waten, John Harding and Jun Yi Ma.
Jennen has performed over fifty concertos as soloist with orchestras in Australia and has toured Asia and Europe as a soloist, Concertmaster of the Australian Youth Orchestra and member of the Australian Chamber Orchestra.
Jennen has acted Guest Concertmaster of the West Australian Symphony Orchestra, Vic Opera Orchestra and Christchurch Symphony Orchestra, and currently performs regularly with the Melbourne Symphony Orchestra, Tasmanian Symphony Orchestra and Melbourne Chamber Orchestra.