Josh Hydes, aged 20, died after the white Mercedes GLS he was driving crashed through railings on Meadowhall Way and plunged into the River Don below last Saturday night.
His uncle Tommy Hydes, 24, also lost his life.
The men were rescued from the submerged vehicle by firefighters and rushed to hospital but despite the efforts of medics could not be saved.
Josh worked in the finance department at the University of Sheffield’s Faculty of Engineering and had just passed some accountancy exams the week before the crash.
His manager Michelle Dickens said: “Josh was a very popular, courteous and conscientious member of our team who always gave his best.
“He was always willing to help others and keen to develop as clearly demonstrated by his excellent progress through his professional Accountancy examinations.
“We were truly lucky indeed to have worked together with Josh. We are all completely devastated by this tragic news.”
Josh’s uncle Tommy – his mum Emma’s half brother – became a dad three months before the crash.
Social media has been flooded with tributes to the popular pair.
Flowers have also been placed at the crash scene, where mourners have gathered to remember the young men.
A police investigation into the circumstances surrounding the collision is under way.
Officers want to hear from anyone with dashcam footage of the crash or anyone who saw the Mercedes before it hit the water.