He was the son of Louis Botha and his wife, Salomina van Rooyen. In 1869 the family left Natal and settled near Vrede in the Orange Free State, where Louis lived until he was twenty-two.
Although Botha had little formal education he mastered the ways of the veldt and developed an eye for terrain - a decisive factor in his later success as Boer commander. His first experience of warfare was in May 1884 when he helped to establish Dinizulu as Zulu king. In 1886 he settled on his farm, east of Vryheid in the newly established New Republic. On 13 December 1886 he married Annie Emmett. Botha was elected field-cornet for Vryheid and retained his office when the New Republic was united with the ZAR in 1888. In 1896 he entered politics when he and Lucas Meyer were chosen to represent Vryheid in the First Volksraad.
With the outbreak of the war in October 1899 Botha joined the Vryheid commando. At the battle of Talana (20/10/1899), Botha took part as an ordinary burgher. He showed the first signs of military genius when General George White, commanding officer of the British garrison at Ladysmith, launched an attack on the Boer forces surrounding Ladysmith on 30 October 1899. With Lucas Meyer ill, Botha thwarted the planned attack of Pepworth Hill. Botha now took over Meyer's command and was appointed general in a permanent capacity. On 14 November he crossed the Tukhela at Colenso. On 15 November he took part in the train derailment at Chievely where Winston Churchill was taken prisoner. On 23 November his men succeeded in routing the troops under Colonel FW Kitchener from Brynbella Hill. When General Piet Joubert became ill Botha was placed in command of the burghers along the Thukela.
Sir Redvers Buller's main objective was the relief Ladysmith. By mid-December he had amassed more than 21 000 troops equipped with forty-six guns south of the Thukela. In the hills along the northern bank Botha and his 4 500 men armed with five guns dug themselves in an excellent position because of the vantage point it offered. From 13 to 14 December Buller directed a heavy bombardment at the hills north of Colenso. Inadequate reconnaissance however, on the British side had failed to detect the positions of the Boer entrenchments. On the morning of the 15th the Boers unleashed a hail of rifle and gun fire from their concealed positions on the advancing enemy across the Thukela which ended in a general British retreat.
In January 1900 Botha deployed his men in a line, 24 km long, opposite three fords on the Upper Thukela. After British troops under Lieutenant-General Sir Charles Warren crossed the Thukela at Trichardtsdrift on 16 January, Botha set up positions on the crest of Tabanyama that were invisible to the enemy. The British attacked on 20 January and for two days mercilessly bombarded Tabanyama. On 22 January they decided to take Spioenkop. Here the column of 2000 men under Major-General E.R.P. Woodgate was pinned down by the Boers on the morning of 24 January. The Boers stormed up Spioenkop and opened fire on the British with deadly accuracy. They were also supported from the surrounding hills. Losses on both sides were severe and by nightfall the British had to evacuate.
On 6 February, Botha resumed command on the upper Thukela. Through careful planning and tactical skill, Botha, who only had 3 510 men and eight guns at his disposal, managed to outwit the British and to keep them guessing as to the true strength of his army. Buller's final assault on the Boer positions at the Thukela however proved too strong. After the conquest of Cingolo (17 February) and Monte Cristo (18 February) the Boer's resistance crumbled. Botha nevertheless offered stubborn resistance at Wynne's Hill, Pietershoogte and Railway Hill (27 February). The British were victorious and the Boers had to retreat, leaving the road to Ladysmith open. A day later the demoralized Boers were on their way to the Biggarsberg and Van Reenen.
By the end of the month was appointed Commandant-General after the death of Joubert. Botha was then placed in charge of the Boer forces in the Free State who were to check Roberts' advance on Pretoria. He arrived at the Sand River with 3 000 men on 7 May 1900 and deployed his men. The numerical superiority of the British proved too great and after French had pushed past Botha's right flank, Roberts' main force was able to break through with ease and to occupy Kroonstad on 12 May.
On 22 May Botha crossed the Vaal River and decided to defend Johannesburg at Kliprivierberg and Doornkop but the British broke through the Boer lines on 29 May and two days later Johannesburg and the mines of the Witwatersrand were in Roberts' hands. Roberts marched into Pretoria shortly afterwards. Botha now took up position at Donkerhoek, east of Pretoria. He made certain that his flanks were strongly manned despite the 48-km line he had to defend. The battle raged for two days (from 11 June to 12 June 1900). After Ian Hamilton broke through the Boer lines the Boers retreated in an easterly direction along the railway line.
In July and August 1900 he was involved in a series of skirmishes with British divisions in the South-Eastern Transvaal always with the protection of the strategically important Delagoa Bay railway line in mind. When the British occupied Middelburg on 27 July 1900 Botha set up his headquarters close to Belfast where he was involved the battle at Bergendal (Dalmanutha) on 27/08/1900. Roberts's superiority in artillery was decisive and the Transvalers were forced to retreat further to the east. Firmly convinced that he had dealt the Boers a mortal blow, Roberts formally annexed Transvaal on 1 September 1900. Although many of Botha's officers were considering surrender at this time, both Presidents Steyn and Kruger bolstered Botha's courage. After Bergendal he abandoned conventional deployment methods. With renewed zeal he moved to Lydenburg where he took up position. Buller routed him from there on 8 September but not before his guns and supplies had been sent away. He now retreated to the Nelspruit railway line. The Boers' prospects looked grim: they were cut off from their supply base and from communication with the outside world. President Kruger had left for Europe and many Boers had fled across the border to Mozambique. Botha nevertheless still had the hard core of his men at his disposal and he was determined to carry on fighting.
In November 1900 Botha reorganized his commandos again; announcing punitive measure for Boers evading commando service and from 2-12 December personally took part in attacks on Utrecht, Wakkerstroom and Vryheid, and Nooitgedacht (12-13 December). After the successful raid on Helvetia (28/29 December) Botha planned a large-scale attack on the various stations on the Delagoa Bay railway line for January 1900 but his forces were too spread out to inflict much damage.
After a meeting with Lord Kitchener at Middelburg in February 1901 he rejected the British peace proposals and continued with the war. He undertook a daring but unsuccessful raid into Natal in September 1901. On 30 October 1901 Botha defeated Lieutenant-Colonel GE Benson at Bakenlaagte. Though there where several skirmishes in Eastern Transvaal during the latter part of 1901 they had little effect on the outcome of the war.
At the Klerksdorp peace discussions and at the negotiations at Vereeniging (15 May -31 May 1902) he agreed with the decision that peace should be declared. During the negotiations with Kitchener and Milner he insisted on an honourable peace for all parties. Two months later he accompanied Generals CR de Wet and J.H. de la Rey to Europe to collect money for the economic recovery of those Afrikaners whom the war had impoverished.
In May 1904 Botha was a founder member of the political party, Het Volk. When self-government was finally granted, Botha became Prime Minister of the Transvaal and with the establishment of the Union of South Africa (1910) he was appointed Prime Minister of the Union. Botha commanded the Union troops during the rebellion of 1914 and the South West African campaign during the First World War. He and General Smuts attended the peace conference in Europe in December 1918 as members of the British delegation, but took their seats as full-fledged delegates in their own right. On 27 August 1919 he died unexpectedly of a heart attack in Pretoria.