Derek Ogg was called to the bar in 1989.
In 2007 he took silk, and shortly afterwards joined the Crown Office as a senior Advocate Depute. In 2009, he was appointed Assistant Principal Advocate Depute. During his time as an Advocate Depute he successfully prosecuted a number of high-profile cases on behalf of the Crown, notably HMA V Webster, which holds the record for the longest criminal trial of a single accused in Scottish legal history. In 2011, he resigned his commission and returned to practice at the defence bar.
In March 2012, he was instructed as lead defence counsel for Ross Monaghan in his controversial trial for the murder of Glasgow gangland figure Kevin Carroll. He was instructed in the case at short notice following the death of Mr. Monaghan's counsel Paul McBride. On 3 May 2012, Ross Monaghan was acquitted by the trial judge Lord Brailsford, following a defence submission under section 97 of the Criminal Procedure (Scotland) Act 1995, that Mr. Monaghan had no case to answer in respect of the charges libelled, due to an insufficiency of evidence. Immediately following the ruling, the Crown lodged a notice of intention to appeal the decision, however the following day this was formally withdrawn.