Early career Jenner started playing football at amateur club DVV Delft. Afterwards, he played for one year at
Feyenoord, before returning to DVV and later playing for
TONEGIDO. Jenner then moved to the youth academy of
DHC, where his father was a coach. He was part of a talented team at DHC, and was invited to trials with
Ajax and
NAC Breda, eventually choosing to join the latter. In the following season, Jenner was unable to make a definitive break through and he only played 5 games in which he managed to score once. In the 2005–06 season, Jenner was able to consolidate himself as a starter for NAC. He played alongside
Pierre van Hooijdonk and
Johan Vonlanthen in attack, among others. In the summer of 2006, Jenner left for AZ, a team coached by
Louis van Gaal, where he was seen as the replacement of
Stein Huysegems who had moved to Feyenoord. In the 2006–07 season, Jenner came on as a substitute in the
UEFA Cup game against Czech club
Slovan Liberec. He scored the 2–2 equaliser in the 89th minute – a chip ball over goalkeeper
Marek Čech – which secured AZ's advancement to the third round. The club finished the season in disappointing fashion, losing out on the
Eredivisie title by three points, and losing to Ajax in the subsequent play-offs for a place in the
UEFA Champions League. In his first season he made 21 appearances, partly due to a change of head coach. Where his first coach
Hans Westerhof utilised Jenner as a winger, his successor
Theo Bos played a system without wingers. In his second season, Jenner played four games with Vitesse and was sent on a six-month loan to
Rot-Weiss Ahlen in the
2. Bundesliga in January 2010. There, Jenner played eleven games and scored one goal. When he returned to
Arnhem in the summer of 2010, Jenner indicated that he was ready to stay to challenge for a place in the starting lineup. on the last day of the transfer window, Vitesse sent him on loan to NAC Breda for the rest of the season. In the summer of 2011, Jenner returned to Vitesse.
Later career In September 2012, Jenner signed with Hungarian club
Ferencváros. After two years with the Hungarian club, Jenner retired from football on 9 September 2014 and announced that he would continue as a youth coach at his former club Vitesse. A month and a half later he accepted an offer from
Diósgyőr and continued his active career. In July 2015, after a week of trial, Jenner signed a one-year contract with
Notts County, who had just suffered relegation to the
EFL League Two. Jenner was reunited with fellow countryman
Ricardo Moniz, who was also his manager at Ferencváros in the 2012–13 season. After the resignation of Moniz, he left the club at the end of January 2016 and retired from football. After his active football career, Julian Jenner married a Hungarian citizen woman. He is currently an assistant coach and personal development coach at the Hungarian football club MTK. ==International career==