Orrock's on-field career began locally at Kinghorn Thistle before the family moved across and up the river to Grangemouth in the early 1900s. There he stepped up to junior football with Forth Rangers, to the senior game for two seasons with Falkirk's East Stirlingshire and then in 1908 to Falkirk itself, captaining the club to that Cup success in 1913. And in the meantime in 1905 he had married, his wife, Isabella Taylor, also from Kinghorn, with whom he was to have four children, all Grangemouth-born.

His time with The Bairns was officially to come to an end in 1917 but the War had effectively meant that in his late twenties football for him might have finished. But he was able even at thirty-two to pursue it once more with two seasons from 1917 at St. Mirren and four more with Alloa, there in 1922 at the age of almost thirty-seven achieving promotion to the First Division from the just formed Second. 

In fact there was to be just one more season in the the Orrock legs at Alloa, to where he had move the family, he recorded as working as a Rivetter in a shipyard. But still that was not the end of his almost bionic playing or of success. As The Wasps had moved into the top-flight East Stirlingshire had finished in mid-table. But the following season it was relegated to the newly-created Third Division, at which point not just Bobby, after a summer tour to South America guesting for Third Lanark, returned but the club immediately bounced back. 

Bobby Orrock would continue on for another campaign with The Shire before trying player-management at Nairn County, where a bad injury forced him not just to hang up the boots but finally at forty leave the game behind. He returned to riveting, seemingly moving back to Falkirk, for that is where Isabella was to pass away in 1954 at the age of seventy, perhaps then to Fife once more to Burntisland, but ultimately to Coatbridge. It is there he was to die in 1969 at the age of eighty-four.