Lushington was a lifelong advocate of the anti-slavery cause.
He committed much time to it, and had significant influence in the British abolitionist movement.
His brother Sir Henry Lushington, 2nd Baronet was a joint owner in 1817 of the Greenwood estate in Jamaica.
He was married to Frances Maria Lewis, daughter of Matthew Lewis who owned estates in Jamaica; and worked in Boldero & Lushington, a bank founded by his maternal grandfather John Boldero and offering mortgages on West Indian plantations.
Other family members were also slave owners or beneficiaries.
Those include William Lushington MP (1747–1823), Stephen Lushington's uncle, and another brother, Charles Lushington (1785–1866), with his wife Sarah Gascoyne a beneficiary of the Jamaica Clarendon Seven Plantations estates.

On his return to Parliament in 1821, Lushington supported William Wilberforce's call on the government to put pressure on countries still allowing the slave trade, and opposed relief for West Indian sugar estates.
He succeeded in having a Slave Trade Acts consolidation bill passed, as the Slave Trade Act 1824.
It included legislation classifying the slave traffic as piracy, and saw the end of trading in slaves between the colonies of the British Empire.
Around this time he began to work closely with the abolitionist leader Thomas Foxwell Buxton.

In 1824–5, Lushington championed the cause of Louis Celeste Lecesne.
Lecesne and John Escoffery were free people of colour expelled from Jamaica, and subsequently involved in a libel suit with George Wilson Bridges.
Lushington argued in the House of Commons in an 1824 speech that they had been subject to discrimination based on skin colour detrimental to their constitutional rights.
Lecesne and Escoffery were both slave-owners, a fact that Lushington took as establishing their social position.
In March 1827, Lushington spoke in Parliament about a sermon given by Bridges in St Ann Parish, Jamaica against missionaries, and an attack on a mission house there.

With Buxton, William Allen, Thomas Hodgkin and Richard King, Lushington was one of the leaders of the Aborigines' Protection Society.
When Hodgkin clashed at Guy's Hospital with the administrator Benjamin Harrison at Guy's Hospital, Lushington took his side, as did Ebenezer Pye-Smith of the staff.

Lushington and his daughters were part of the group of abolitionists who supported the education of the fugitives Ellen and William Craft in the early 1850s.
It took place in the school at Ockham founded by Lady Byron.
Lushington was a lifelong advocate of the anti-slavery cause. He committed much time to it, and had significant influence in the British abolitionist movement. His brother Sir Henry Lushington, 2nd Baronet was a joint owner in 1817 of the Greenwood estate in Jamaica. He was married to Frances Maria Lewis, daughter of Matthew Lewis who owned estates in Jamaica; and worked in Boldero & Lushington, a bank founded by his maternal grandfather John Boldero and offering mortgages on West Indian plantations. Other family members were also slave owners or beneficiaries. Those include William Lushington MP (1747–1823), Stephen Lushington's uncle, and another brother, Charles Lushington (1785–1866), with his wife Sarah Gascoyne a beneficiary of the Jamaica Clarendon Seven Plantations estates.
On his return to Parliament in 1821, Lushington supported William Wilberforce's call on the government to put pressure on countries still allowing the slave trade, and opposed relief for West Indian sugar estates. He succeeded in having a Slave Trade Acts consolidation bill passed, as the Slave Trade Act 1824. It included legislation classifying the slave traffic as piracy, and saw the end of trading in slaves between the colonies of the British Empire. Around this time he began to work closely with the abolitionist leader Thomas Foxwell Buxton.
In 1824–5, Lushington championed the cause of Louis Celeste Lecesne. Lecesne and John Escoffery were free people of colour expelled from Jamaica, and subsequently involved in a libel suit with George Wilson Bridges. Lushington argued in the House of Commons in an 1824 speech that they had been subject to discrimination based on skin colour detrimental to their constitutional rights. Lecesne and Escoffery were both slave-owners, a fact that Lushington took as establishing their social position. In March 1827, Lushington spoke in Parliament about a sermon given by Bridges in St Ann Parish, Jamaica against missionaries, and an attack on a mission house there.
With Buxton, William Allen, Thomas Hodgkin and Richard King, Lushington was one of the leaders of the Aborigines' Protection Society. When Hodgkin clashed at Guy's Hospital with the administrator Benjamin Harrison at Guy's Hospital, Lushington took his side, as did Ebenezer Pye-Smith of the staff.
Lushington and his daughters were part of the group of abolitionists who supported the education of the fugitives Ellen and William Craft in the early 1850s. It took place in the school at Ockham founded by Lady Byron.
Stephen Lushington (judge)