In 2000 he joined the newly formed Oceanlab at the University of Aberdeen as mechanical technician where he also completed a part time PhD entitled Autonomous lander technology for biological research at mid-water, abyssal and hadal depths,[6] graduating in 2004.

He completed two EU funded postdocs, the first a sediment dynamics project named COBO (Coastal Ocean Benthic Observatories[10]), that involved the design and construction of a deep-water Sediment Profile Imaging camera (SPI), the second was an astrophysics project named KM3NeT (Cubic Kilometre Neutrino Telescope), where he surveyed deep-water pelagic bioluminescence across potential sites for an underwater neutrino telescope[11] in the Mediterranean.

The vehicle was lost during this expedition,[22] but by using spare parts and scrap metal, Jamieson constructed a full ocean depth lander, known as the Wee Trap, that days later captured the deepest fish ever caught, Pseudoliparis swirei.

[23] On the second expedition, to the Mariana Trench, he set a new record for the deepest fish (the 'Ethereal snailfish' at 8145 metres deep) and the first video footage of the supergiant amphipod, Alicella gigantea.

In March 2020 he was Chief Scientific on the Phase III expedition to the deepest point of the Red Sea (Suakin Trough), where Jamieson and Vescovo successfully explored the Kebrit Brine Pool in the submersible.

[41] In 2021 he led a Minderoo Foundation charter on the DSSV Pressure Drop to the East Indian Ocean where he completed six submersible dives to the Wallaby-Zenith Fracture Zone and Wallaby Cuvier Escarpment between depth of 6600 and 4400 metres.

[43] Notable publications include a paper entitled Bioaccumulation of persistent organic pollutants in the deepest ocean fauna,[44] published in Nature ecology & evolution, Fishes of the hadal zone including new species, in situ observations and depth records of Liparidae,[45] published in 2016 in the journal Deep Sea Research Part I. Jamieson was part of the team that led to the discovery of microplastics at full ocean depth,[46] and was involved in a recent campaign with the WWF (Call it plastic) to name a hadal species Eurythenes plasticus.

[47][48] Since 2020, he has co-hosted The Deep-Sea Podcast[49] with Dr Thom Linley of Armatus Oceanic and Captain Don Walsh known from the 1960 Bathyscape Trieste dive to the Mariana Trench.

During this time he has interviewed notable guests such as Dr Glenn Singleman, author Susan Casey, UN secretary General Michael Lodge, His Serene Highness Prince Albert II of Monaco, and film director James Cameron, among others.

In episode 13,[50] he interviewed Australian submersible pilot Tim Macdonald of Caladan Oceanic at a depth of over 10,000 metres in the Philippine Trench from inside the DSV Limiting Factor.