Magherafelt R.F.C. was founded in 1928. Some success at minor level came the club's way before the outbreak of war. A few games were played during the war years and from 1947, the club became known as Rainey Old Boys R.F.C. After initial success, a barren period followed and it was not until the mid-60s that the club began to go places.
Having added some strength in depth to the squad, they started the next season by beating Ballymena 2s in the Past Players' Cup Final. After twelve straight wins in the league, they came unstuck at
In 2008/09, With South African Rhys Botha as Player/Coach and Andrew Kerr as Captain, Rainey turned in some very promising performances in the Ulster League, beating Ballymena once again at Eaton Park. A fine victory over Instonians at Shaw's Bridge earned them a home tie against U.C.D. in the second round.
They opened their AIL campaign with a win at Banbridge, but their aspirations of a top four finish disappeared when player after player joined the injured list, including Willem Jacobs, an overseas recruit from South Africa. While their home form was strangely poor, they produced some battling displays at Suttonians, Ards and Sunday's Well to finish in 10th place.
Richard McCrea was captain for season 2009-2010. Forty-seven players were used as player after player went down injured. Limerick side Old Crescent were visitors in the Cup before the AIL got under way. New Zealander Tony Dodunski picked up an injury within five minutes of his debut and was out for six weeks. Hopes of a top half finish turned to survival and a narrow victory at Portadown proved vital. An unexpected draw at Midleton, who were promoted behind an outstanding Queen's team, was a timely boost and late season home wins over Instonians and Ards took Rainey up to the thirty point mark and again tenth spot in the table.
Season 2010-2011, with Rodney Paul as captain, was a truly remarkable one. A chronic injury list saw the side struggle in the Ulster League and lose the first four games in Division 3 of the AIL campaign, but the return to fitness of New Zealand scrum-half Peter Sciascia and a host of others kick-started an outstanding run, spoiled only by an intercept try against Nenagh. A record total of 46 points hoisted Rainey up to sixth place.
This run of success continued when Simon Hawe took over as captain. After a great start, a little mid-season sticky patch was to severely dent promotion prospects, but a fine finish earned the club fifth place on 48 points in Div 2B of a restructured AIL. The ability and character of the squad was evident when all-conquering Cashel were extremely fortunate to beat them 20-17 at Spafield on the final day of the campaign. Neil O'Kane was chosen as Player of the Year for the fifth time, while the very popular Peter Sciascia returned home, having given the club many moments to remember.