Jesse Gordon Spencer (born 12 February 1979) is an Australian-American actor and musician. He is known for his roles as Billy Kennedy on the Australian soap opera Neighbours (1994–2000, 2005, 2022), Robert Chase on the American medical drama House (2004–2012) and Captain Matthew Casey on the American drama Chicago Fire (2012–present).

Early life
Spencer was born in Melbourne on 12 February 1979 to Rodney Spencer, a radiologist, and Robyn Spencer, who were founders of the Australians Against Further Immigration political party, and would both later contest the 1998 federal election for One Nation.

He is one of four siblings. Spencer has two older brothers: Tarney Spencer, an oculoplastic surgeon, and Luke Spencer, an orthopaedic surgeon. His younger sister, Polly Spencer, is an anaesthetist. Growing up, he attended Canterbury Primary School, Malvern Central School, and the private Scotch College. While there, he auditioned for the long-running soap opera Neighbours. He completed his VCE and had gained a place at Monash University but deferred to pursue acting.