David Tod was born in Colen, parish of Scone, Perthshire, on 17 May 1795. He was the fifth child of Thomas Tod and Elspet Gray and his father was a farm servant at the time of his birth. The evidence indicates that Tod, senior died in 1808 – when David was nearly thirteen – and it may be that he left home shortly afterwards to start an apprenticeship. David Tod married Jane Walker in Barony Church, Glasgow, on 6^th July 1823. She was born in 1899 in Old Monkland, Lanarkshire. They had eight children, three of whom – all boys – reached maturity.

David Tod was chosen to be chief engineer on board David Napier’s pioneer paddle steamer ship ‘Rob Roy’, built by Denny of Dumbarton and engined by Napier from 1818 to 1821.

Rob Roy was about 80 ft long with a beam of 16 ft and had a Napier side-lever engine of 32 hp which gave her a speed of 7 knots. She was not only the first regular seagoing steamer in the world, but was also the first steamer to have had the shape of her hull based on the behaviour of ship models in an experimental water tank. She left the Clyde early on Saturday 13th June 1818 and, after calling at Campbeltown, arrived at Belfast on Sunday evening. Among those who wished her well was Charles MacKintosh the inventor of waterproof cloth. No one expected her to reach Ireland but she got across, and later in the same year she made some trips between Greenock and Dublin.

During her first season Rob Roy normally provided a bi-weekly service between Belfast and Greenock, with a call at Campbeltown en route. In the winter of 1818-1819 the Rob Roy had an extensive overhaul. On return to duty in March 1819 the local newspapers commented favourably on her improved accommodation which comprised 'separate apartments for ladies and gentlemen fitted up with beds and other accommodation which experience has pointed out necessary'. She remained on the Belfast-Greenock crossing until her transfer to the Dover-Calais route in May 1821,[Irish Passenger Steamship Services, D.B. McNeill] at which time David Tod returned to David Napier's Lancefield works.

By 1830 he was a senior employee of Napiers at Lancefield. By the early 1830s still under the age of fifty, David Napier appeared to feel that his pioneering engineering achievements in Scotland were at an end as he considered a move to London; by 1835 he had disposed of his Glasgow interests and moved.

It has been said that David Napier offered Lancefield Foundry to two of his employees, David Tod and John Macgregor. His regard for both of them is set down in a memoir which he wrote subsequently: “During the latter part of my career, I was very much assisted by two excellent workmen, David Tod and John Macgregor”. His offer of the foundry was not taken up, the two perhaps deciding to start at a more modest level.

One of the stories which describes the relationship between David Napier and David Tod relates to the night that Napier first conceived the idea of the steeple engine. It occurred at midnight, when Napier was in bed. He immediately got up, cleared his dining room of its furniture and carpet and drew his rough plans with chalk on the floor. A servant was sent off for Tod who rushed to the house thinking that his employer was ill. Then the pattern maker who acted as Napier’s draughtsman was sent for and the first set of rough plans were completed by morning.

Tod and John Macgregor set up business together initially to produce engines, but later they started to build ships. As a business Tod & Macgregor was immensely successful.

In the period running up to 1852, David Tod was one of the leading figures in Partick, who were campaigning for the creation of a separate Borough. The campaign was successful and on the 17^th of June 1852 the Borough of Partick was created. In the first election, 12 commissioners were elected. David Tod was elected for the "Iron Bank" ward and was picked as one of the three "Magistrates" of the Borough. From these three the "Provost" was picked and it was David Tod they turned to. He remained Provost for five years until 1857.