Jagger is a surname.
In England someone who owned and/or managed a team of packhorses was known as a "jagger", so this English surname probably originates from that occupation.
Notable people with the surname include:
Amy Jagger (1908–1993), British gymnast
Bianca Jagger (born 1945), human rights advocate
Charles Sargeant Jagger (1885-1934), sculptor
David Jagger (1891–1958), English portrait painter
Dean Jagger (1903–1991), American actor
Elizabeth Jagger (born 1984)
Jade Jagger, jewellery designer; daughter of Mick and Bianca Jagger
Joseph Jagger (1830–1892), British engineer
Mick Jagger (born 1943), lead singer of The Rolling Stones
Fictional characters:
Jagger Cates
Thomas Jagger
Mr Jaggers in Great Expectations
Other uses
"Jagger", the offspring of a male jaguar and a female tiger
