Cross entered professional rugby when he joined Border Reivers in 2003 from Heriot's after having played for Scotland under-21 that year, including being at tight-head in the team who beat England 33–22 at Newbury in the final match of the age group's world championship.
In December 2006 Cross moved from the Border Reivers to Edinburgh on loan until the end of the season, and his debut for the capital city's team followed later that month in the Celtic League game against Glasgow Warriors at Hughenden.
Cross's loan to Warriors lasted to the end of the season where he signed for Aviva Premiership side London Irish once his contract with Edinburgh expired.
He was encouraged to cultivate during a loan spell at Glasgow Warriors by team-mate – and similarly bearded wonder – Josh Strauss: I was at Glasgow for ten weeks last season and I talked to Josh Strauss, and he said, 'You know, Geoff, you say that after rugby you’re going to work as a medic, and I see you haven’t shaved for a few days – really I don’t think very many people would be happy if they went to a GP practice to talk about their sore back, looking to be reassured, and there was this man with this enormous beard.
You should seize that opportunity.The hirsute prop's face was eventually shaved by London Irish teammates on the last day of March 2015 (much to the delight of his wife, Helen), having raised over £10,000 for the Wooden Spoon charity.