The private investigator regularly commissioned by senior editors at the News of the World was "generally known" by staff to be part of the paper's "special investigations team", the Old Bailey has heard.
Geoff Sweet, a reporter who interviewed Glenn Mulcaire in 2002, said he knew him as someone who worked for the now-shuttered Murdoch-owned tabloid.
The former chief executive of News International, Rebekah Brooks, and the former editor of the NOTW, Andy Coulson, are among eight defendants facing hacking-related charges. All the charges are denied.
Ms Brooks, the prosecution alleged earlier in the trial, has stated that she did not know who Mulcaire was during the time she edited the NOTW between 2000 and 2003.
Mr Sweet said he interviewed Mulcaire for a "novelty story" that focused on his previous job as a footballer. The story mentioned his link to the "special investigations team".
The jury heard how this information on Mulcaire was included. Mr Sweet said : "I knew [him] to be the centre forward for Wimbledon" adding "I understood he was part of the special investigations team and because I was part of the News of the World empire, it was just generally known."
Questioned by Mrs Brooks' lawyer, Mr Sweet said he was not based permanently at Wapping, the paper's main office, and visited only once every six weeks or so. He added that Mulcaire - who was jailed in 2007 on hacking charges, and pleaded guilty to other hacking-related charges earlier in the trial's progress - "was never discussed" at the newspaper's office.
Mr Sweet also admitted he could not remember writing the Mulcaire story, stating the information on the "investigations" role could have added in by someone on the sports desk.
The trial continues.