After receiving his wings, he was attached to No. 37 (Home Defence) Squadron at Sutton's Farm,
Essex flying the
BE.2c. He soon requested a transfer to France.
In March 1917, he was posted to 60 Squadron at Filescamp Farm near
Arras, flying the
Nieuport 17 fighter. At that time, the average lifespan of a new pilot in that sector was 11 days. Bishop claimed his first victory on
25 March, when his was one of four Nieuports that engaged three
Albatros D.III Scouts near St Leger, shooting down and mortally wounding a Lieutenant Theiler. Bishop, in addition to the usual patrols with his squadron comrades, soon flew many unofficial "lone-wolf" missions deep into enemy territory, with the blessing of his CO, Major
AJL Scott. As a result his total increased rapidly. On
8 April, he scored his fifth victory and became an ace. To celebrate, he had the cowling and struts of his fighter painted bright blue. This was probably inspired by the red spinners on the aircraft of fellow squadron member Captain
Albert Ball, at that time the Empire's highest scoring ace. He claimed 12 aircraft in April alone, winning the
Military Cross and a promotion to Captain for his participation at the
Battle of Vimy Ridge. On
30 April, Bishop claimed to have survived an encounter with
Manfred von Richthofen, the Red Baron, although it is more likely that Bishop had actually been fighting other members of Richthofen's
Jasta. In May, Bishop won the
Distinguished Service Order for shooting down two aircraft while being attacked by four others.
Bishop was always "at the front of the pack," leading his pilots into battle over hostile territory. One fellow pilot account claims “normal formation is two at the front and three at the rear, except Billy was always at least ½ mile ahead, how he got that far I do not know”.