The first cross-country run took place on 13th January, 1872 and later that season, 9 members ran "the longest Hare and Hounds run on record, about 29 miles".

The steady spread of London's suburbs forced the Club to move from Peckham to Streatham in 1877, then to Balham, and later to Croydon and finally to Coulsdon in 1913, where it acquired it own freehold premises (an old church hall) as HQ in 1933.

SLH competed in the first "National" and most races since then, but did not win it until 1955, when it won all three team titles (which no other club has ever done) and had the individual winner in Gordon Pirie, with Roly Langridge 2nd in the Youths. The Club won the "National" again in 1957 and 1958. It won the first "Southern" and its total of 13 wins is only 1 less than Highgate's 14 record. Thirteen members have represented their countries in the "International", which Alfred Shrubb won in 1903 and 1904. Despite the circumstances of its foundation, SLH maintained good relations with Blackheath Harriers from the start and since 1896 the two Clubs have met in 74 "Nicholls" Cup Mob Matches, of which SLH have now won 38 to BH's 36. Other old-established Mob Matches are with Ranelagh (1909) and Orion (1920), in both of which SLH has big leads.

SLH promoted its first open track meeting on 24th August, 1872 at Dulwich - it was a financial loss, as were many of the famous Oval Meetings, which began in 1875; the last was in 1927.

On the track SLH has held three World Record holders: Shrubb, Pirie and Ibbotson, and has had AAA Champions in most events. Olympic medallists are Gordon Pirie (2nd 5000m in 1956). Derek Ibbotson (3rd in 5000, 1956) and Tom Richards 2nd in the Marathon (1948). Derek Pugh won the European 400m in 1950, Jack Parker was 2nd in the European 110m Hurdles in 1954, Harold Moody 2nd in the Empire Shot in 1950. Gordon Miller set the UK High Jump record (1964) AT 6' 10 1/2" (2.09m) and represented GB in the Olympics.

In 1954, Peter Driver (7th in the International CCC) won the AAA 6 Miles and the Empire 6 Miles in a new record time.

In Road-Running events SLH has a distinguished record: winning the old London-Brighton Relay in four successive years (1955-58) and the team race in the London to Brighton in 1977, 1978 and 1981, as well as the Isle of Man 40 miles on 6 occassions. Tom Roden and Mike Newton have been amongst the leading "Ultra" distance runners in recent years.

The Club has played a leading part in administration since the early years, when it assisted at the formation of the AAA, the Southern C-C A and the ECCU. It has the unique record of having provided the IAAF with its Hon. Secretarty-Treasurer from 1946 to 1976, that office being held by Billy Holt (1946-52), Don Pain (1952-69) and Fred Holder (1969-76) and Holder is still Hon. Treasurer. Holt had been AAA Treasurer and Secretary, Hon. Secretary of the BAAB, Director of Organisation at the Wembley Olympics in 1948. The tradition of providing administrators has faded in recent years and at present on Bert Liffen holds office as a Vice-President of the AAA, after serving at all levels as an official since he was an International sprinter just after the War.

For 41 years the Club has promoted a 30 Miles Road Race, the only race over this distance in the UK, and has won the team race on 16 occasions.

The Club's magazine - The SLH Gazette and Club Chronicle - is now in its 100th year of unbroken publication; originally a monthly it now appears only three times a year.

A ladies section was formed recently and is developing steadily.

Very early in its history, SLH members were nick-named "Irrepressibles", probably before 1885, when they justified it by winning the "Southern" despite the loss of half of the expected scoring six, due to a series of misfortunes.