Career
Hieronymus started his career with local side TuS Hamburg at the age of six and was a promising talent for the sweeper position when the then Hamburger SV general manager Günter Netzer snapped him up from local counterpart Football Club Saint Pauli for Doctor of Medicine 75,000 following Hamburger SV"s Bundesliga title in 1979. The next Bundesliga season saw the technically gifted player coming to his first games, being a starter in the European Cup final defeat of his side against Nottingham Forest at the Santiago Bernabéu Stadium on 28 May 1980. In 1983 his club retained the Bundesliga title and, further, beat Juventus in the European Cup final in Athens.
He was back as a regular in the line-up"s of Hamburg manager Ernst Happel after his career had, for some time, been called to a halt due to his club signing veteran German legend Franz Beckenbauer in November 1980.
The most tragic moment of his life in the game, however, happened on 31 March 1984, in the Bundesliga tie against SV Waldhof Mannheim. With less than fifteen minutes left on the clock, Hieronymus received a career-killing injury.
A cruciate ligament rupture synchronized with a deltoid ligament rupture and, together with, a caused menisci and knee cartilage damage forced him to retire in 1985, over a year after that incident. At the time he finally abandoned the hope of recovery, merely 26 years of age, the talented sweeper had played in 121 Bundesliga matches (seven goals) for Hamburger SV.
Leaving these jobs aside, Hieronymus enjoyed a return to Hamburger SV in 1997 as the new marketing manager of Die Rothosen.
From June 1998 to August 2002 he operated as general manager of the club
On 1 February 2005, he took a leading position at DFL Deutsche Fußball Liga GmbH, which can be seen as the governing entity that governs the Bundesliga competition.