He married Sarah Gaynor (1 January 1892 – 19 August 1978) from Inchicore in Dublin, in 1914, and had six children, William, David, Jr. ("Dave"), Annie, Mona, John, and Stephanie.
[citation needed] Modern business methods were developed, such as "cash and carry" wholesaling in 1964, and incentive schemes for workers were introduced.
[citation needed] Politicians such as Taoisigh (Irish Prime Ministers) Éamon de Valera, Liam Cosgrave, and Jack Lynch supported business initiatives by David P. Tyndall and his sons.
[citation needed] Tyndall held a lifelong interest in horse-racing, and at one time owned a number of racehorses.
[citation needed] Former Taoiseach (Prime Minister), Liam Cosgrave, and other leaders of the political, business, and community sectors attended David P. Tyndall's funeral in 1970.