Hartley was born in Dumbarton, Scotland and was the son of a tailor.[1] After youth football with Artizan Thistle, he joined Dumbarton, where two of his brothers also played, in 1890. During his time with Dumbarton, he converted from a right back to a forward.[1] While on the books of Dumbarton, the team won the first two Scottish Football League titles in 1891 and 1892 together with the 1891 Scottish Cup. However Hartley was not a regular with the club at this stage.[5]
Everton
He moved south of the border to join Everton in December 1892, making his debut on 18 March when, playing at inside right, he scored in a 4–2 victory at Wolverhampton Wanderers.[6][7] That was his only appearance in the 1892–93 season in which Everton finished third in the table. The following season, he made six league appearances, scoring twice, following this up with five goals from 11 appearances in the 1894–95 season when Everton finished as runners-up behind Sunderland. During this season he remained third–choice striker behind England internationals, Fred Geary and Jack Southworth.
Following Southworth's retirement through injury and Geary's move to Liverpool, Hartley played more regularly although the arrival of Scotland international John Cameron prevented Hartley from claiming the centre-forward's berth as his own. In the 1895–96 season he made 15 appearances, scoring seven goals as Everton finished in third place followed by 14 appearances with six goals in the following season.
In his five years at Everton, Hartley made 61 appearances, scoring 28 goals; his appearances were restricted due to the quality of forwards on Everton's books such as Geary, Southworth and Cameron as well as other internationals Alf Milward, Edgar Chadwick (both England) and Jack Bell (Scotland).
Liverpool
Hartley stayed at Liverpool for the remainder of the 1897–98 season. During his time with the club he scored the winning goal in a 2–1 away win at Sheffield United on 29 December 1897.
Altogether Hartley was capped a sum of 12 times for Liverpool, scoring once.[10]
By now, Hartley was a member of the Association Footballers' Union which was trying to improve player's wages and contract terms. To improve his wages, Hartley decided to join Southampton.[11]
Hartley was ever-present until injury forced him to sit out the last three matches of the 1898–99 season as Southampton claimed the Southern League title for the third consecutive year. Hartley's 14 league and two FA Cup goals made him joint top scorer for the season (with Harry Wood).[12]
Hartley would place a hand-rolled cigarette behind his ear prior to kick-off and then smoke it in the changing room at half-time before re-taking the field.[1][11]
Arsenal and Burnley
Hartley moved to Woolwich Arsenal in July 1899 where he scored once in five appearances. He made his debut away to Walsall on 23 September 1899 and scored his only goal in a 2–1 win over Gainsborough Trinity on 14 October. However that same month Arsenal signed Ralph Gaudie from Sheffield United, who forced Hartley out of the side.[13][5] Hartley was sold in December, moving back to Lancashire to join Burnley where he brought an end to his playing days.[13] His five goals from thirteen appearances were unable to prevent Burnley being relegated to the Second Division at the end of that season.