In the beginning, the club played only friendly matches before joining the East Northumberland League in 1901.
The first recorded honour being a league success in 1901 followed by further victories in 1905–06 and 1906–07. The club then joined the Northern Alliance, remaining there for six seasons winning the league in 1908–09 and 1912–13.
In 1913 the club moved upward joining the ranks of the semi-professionals in the North Eastern League and remained there until it folded in 1958. The fierce competition meant that honours were few and far between, the league was however won in 1936–37 season and the league cup won in 1950 and again in 1955.
After the demise of the North Eastern League the club tried their luck in the Midland League and Northern Counties League, both ending when the leagues folded. The early 1960s saw the revival of the North Eastern League; however, it was again beset by many problems and would eventually fold for good. The club was now at a loss for a suitable semi-professional league and in 1964 decided to turn amateur and join the ranks of the Northern League. During the 29 years the club were members their record was second to none, winning the Championship on ten occasions and finishing as runners-up five times.
However, a new regime at the club were keen to progress up the league pyramid and a successful push ended with promotion to the Northern Premier League in the 1993–94 season. The club’s first season in the Northern Premier League was memorable, winning the First Division Championship and the Unifilla First Division League Cup. Since gaining promotion the club held its own in the Premier division, as well as lifting the President’s Cup defeating former Conference side Runcorn in the final.
Harry Dunn’s appointment ushered in a period of success for the club, which clinched the Northern Premier League Premier Division - and, with it, promotion - as well as the Northern Premier League Chairman’s Cup and the Peter Swailes Memorial Shield.
In their first season in the Conference North, Blyth finished a respectable 7th, but had to fight hard to retain their league status for the next two consecutive seasons. Dunn departed ahead of the 2009-10 season, and though the Spartans were anchored comfortably in mid- table in the following two years, they won just seven games in their 2011- 12 campaign, and were duly relegated upon finishing second-bottom.
Quality players were not immediately replaced at Croft Park, and the Spartans would return to the NPL with an underwhelming 16th place finish. The arrival of Tom Wade, initially as caretaker towards the back end of the 2012-13 season, would gradually restore Blyth Spartans to its former glory. The club have since become staples in the top half (8th in 2014 and 6th in 2015), lifted the Senior Cup in 2014-15, and were on the cusp of promotion to the Conference North once more, only to suffer a heartbreaking defeat to Workington in the play-off semi-final.