|Full name||William James McCullough|
|Date of birth||27 July 1935|
|Place of birth||Carrickfergus, Northern Ireland|
|Height||5 ft 10 in (1.78 m)|
|Playing position||Left back|
|* Senior club appearances and goals counted for the domestic league only|
Born in Carrickfergus, McCullough first played for Portadown, before being signed in 1958 for £5,000 by London club Arsenal. A left back, he soon made his debut for the club, against Luton Town on 26 December 1958. He only played ten matches that season, but after Len Wills was moved to right back at the start of 1959-60, McCullough became Arsenal's' regular left back.
McCullough became known for his consistency and fitness – he wore the No. 3 shirt for Arsenal for the next six seasons, missing only a handful of matches. Although Arsenal had reached third place in his first season at the club, for the rest of his career in the side the club dwelled in mid-table and never challenged for honours.
He won his first cap for Northern Ireland in a friendly against Italy on 25 April 1961, which Northern Ireland lost 3-2. He went on to appear ten times for his country, scoring no goals, with his final cap coming against England in a 2-0 defeat on 22 October 1966.
By 1965-66, McCullough had competition for his place, in the shape of the young Peter Storey. When Bertie Mee took over at Arsenal at the end of that season, looking to build a young side, he transfer listed the 31-year-old McCullough during the close season. He had played 268 matches in total for Arsenal, scoring 5 goals. He was sold to Millwall in August 1966, and later had spells at Bedford Town, Cork Celtic and Derry City.
- "Billy McCullough". Barry Hugman's Footballers. Retrieved 2 November 2017.
- "Billy McCullough". Arsenal F.C. Retrieved 2 November 2017.
- Sharp, Tom (20 February 2016). "Arsenal legend Billy McCullough discusses becoming a father figure to George Best, joining the Gunners' 100 Club and taking Cork Celtic to the Irish Cup final". Welwyn Hatfield Times. Retrieved 7 April 2017.