The company was the foundation of today's Go-Ahead Group, which now operates bus and rail services across the United Kingdom, as well as Germany, Ireland, Norway and Singapore.

In October 1986, at the time of bus deregulation in Great Britain, the company operated from fourteen depots: Chester-le-Street, Consett, Gateshead, High Spen, Houghton-le-Spring, Jarrow, Murton, Percy Main, South Shields, Stanley, Sunderland, Wallsend, Washington and Winlaton.

[1] Early expansion saw the acquisition of a number of smaller competing bus operators in the region, including Langley Park-based Gypsy Queen in January 1990.

Go-Ahead later took steps to streamline the business, with several of the group's earlier acquisitions transferred to OK.[12] In August 1998, a new depot was opened on Deptford Terrace, Sunderland.

[17][18] In January 2012, as a celebration of the company's centenary year, the OK Motor Services branding was briefly revived, following the introduction of two routes serving Bishop Auckland, Crook and Darlington.

[19][20][21] In June 2018, Hull-based East Yorkshire Motor Services was acquired by the Go-Ahead Group, bringing an end to 30 years of family ownership.

[26][27][28] In December 2019, a "farewell" event was held to mark the retirement of the final remaining Scania L94 vehicles – the first of which joined the fleet in March 2001.

[29][30][31] In July 2020, the company's first fully-electric zero-emission vehicle trial took place, with a single-deck Optare MetroCity serving a series of routes in Gateshead, Newcastle upon Tyne and North Tyneside.

[32] Following this, in November 2020, the first of a fleet of nine zero-emission single-deck Yutong E10 were introduced on routes 53 and 54, as part of a jointly-funded project between Go North East and the UK Government's Ultra-Low Emission Bus Fund – at a cost of £3.7 million.

[44][45] The strike was brought to an end on 1 December 2023, when union members voted in favour of an improved pay offer, with normal service resuming the following day.

[48] As of January 2024, the company operates from seven bus depots across the region: Consett (Hownsgill), Gateshead (Riverside and Saltmeadows Road), Hexham, Percy Main, Sunderland (Deptford) and Washington.

[49] The fleet consists mainly of diesel-powered single and double-deck buses manufactured by Alexander Dennis, Optare, Volvo, Wrightbus and Yutong.

From the late 1990s until the early 2010s, the standard fleet livery consisted of vehicles branded in a red, blue and yellow colour scheme.