Whitfield, Glossop, Derbyshire born centre forward Irvine Thornley began his football career with Glossop Villa in 1899 and played for Glossop St James in 1900 before joining Second Division hometown club Glossop in January 1902, making his debut in an FA Cup tie against Nottingham Forest the same month. He scored on his Football League debut in a 1-1 draw at Blackpool a week later, and soon became a regular goalscorer for the club, top scoring with 17 goals in 1902-03 and 21 goals in 1903-04.
In April 1904 he was signed by First Division Manchester City along with Frank Norgrove. Soon after the Football Association carried out an investigation into the transfer practices of the club and manager Tom Maley (brother of legendary Celtic manager Willie Maley) regarding making additional payments to players to avoid the maximum wage at the time. The investigation led to Maley receiving a life ban from the game and seventeen players were either fined or suspended. With a new squad hastily assembled, City met Arsenal soon after in a match played during a heatwave. With temperatures soaring, Thornley collapsed thirty minutes into the match and was described as “prostrate and very ill”. City went on to lose four other players during the match due to the extreme heat, finishing the match with only six players.
In his second season at the club, he scored 21 League goals in the First Division to finish as the club’s top goalscorer, a feat which he achieved in three consecutive seasons afterwards. He received his first call-up for the England team in 1907, being named as a reserve for a match against Ireland on 16th February 1907 before making his international debut against Wales in a 1-1 draw at Craven Cottage the following month. He also made two appearances for The Football League, playing in a 0-0 draw against The Scottish League in Glasgow in May 1907 and in a 6-3 victory over The Irish League at Roker Park that October.
City were relegated in 1909 but Thornley scored 12 goals as they won the Second Division Championship at the first attempt in 1910. He then played two more seasons in the First Division for them, Thornley’s popularity at City was recognised when his benefit match in 1912 raised a record £1,036 for him. He joined South Shields Adelaide in the summer of 1912 after 93 goals in 204 appearances for The Citizens, and spent three seasons with South Shields playing in the North Eastern League, scoring 154 goals in 130 matches for the club including 70 in one season.
Following the outbreak of the First World War, Thornley joined the Royal Artillery at the age of 32 and served as a gunner until he was discharged in May 1919. His brother John, who played for Manchester United as an amateur, was killed during the War after succumbing to wounds he suffered during the Battle of St. Quentin in March 1918. During the War, Thornley played for Clydebank in 1917 and joined Hamilton Academical after the conflict in 1919, playing a season before joining non league Houghton in 1920 before his retirement.