Mike joined Holby A&E as consultant in series 7. He and Charlie Fairhead made a good team fighting the powers that be for funding. Mike was a popular member of the team.
Mike's marriage broke up towards the beginning of series 9, when his wife left him, taking their children, and he spent that Christmas with Rachel Longworth. Their relationship lasted just a few weeks before his wife asked for a reconciliation, and he went to London to try to rebuild the relationship.
By the beginning of series 10, he had returned to Holby, the marriage over for good. He and Rachel started their relationship again, and shortly afterwards, sick of the way the hospital was being run, he resigned from his job and decided to do voluntary work abroad. He persuaded Rachel to join him. He came back to Holby once more for a short period at the beginning of series 11 before going back to Rachel in Africa.
Mike flew in from Africa for Charlie and Baz's wedding at the end of series 12, but he did not mention Rachel.
During series 14 of Casualty (in series 2 of Holby City), Mike returned to Holby as General Consultant Surgeon on Keller ward. He mentioned that he had been working in the States. We discovered that he and Rachel had split up, and that Rachel was getting married again. When Cassandra Holdsworth, an old friend of Mike's from medical school, turned up on the ward, Mike invited her out for dinner. Cassandra offered him a one-night stand, saying she saying she didn't want any excess baggage in her life but had her needs. Mike turned her down.
Mike was always very friendly with sister Kath Shaughnessy, and often jokingly flirted with her. In the last episode of the series, Mike took some of the Darwin and Keller staff on a team-building excercise. He managed to persuade Kath to come although her husband wanted her to go to some function at his work. Kath and Mike were clowning around a lot, and Kath confessed to Mike that her husband was the only man she'd ever kissed. But things went wrong when Mike stepped onto a trap and fell and rolled down a hill. The others discovered he had broken his leg, and things got more serious as they found out there was air trapped around his heart. Kath was very distressed. Ray Sykes, taking instructions from Meyer by phone, operated successfully to release the air. It seemed that Mike would live, but Meyer didn't know whether they'd be able to save his leg...