His notable television roles include Netflix's Delhi Crime (2019), ITV's Beecham House (2019), Amazon Prime's sitcom Mind the Malhotras (2019) and P.O.W.

He has a long-standing association with both Motley Productions for Waiting for Godot and The Caine Mutiny Court-Martial, and PrimeTime Theatre for Guahar, August: Osage County and Sammy.

A talented singer, Benjamin was granted a leave of absence to represent India as part of the classical cappella Paranjoti Academy Choir for an extended tour of Europe in the 1960s.

[3] Smith began his professional career as a film executive under Indian adman and actor, Alyque Padamsee, who was then CEO of the advertising agency Lintas.

[5] A pivotal play early in his theatrical career was Pearl Padamsee's Les Liaisons Dangereuse where he first worked with Naseeruddin Shah and Ratna Pathak.

Smith also played key roles in numerous other productions such as Jawaharlal Nehru in Letters to a Daughter from Prison (directed by Vijaya Mehta and based on the 1984 publication of Nehru's letters),[13] Jesus in Jesus Christ Superstar in Toronto, Canada, Vali and Vibishan in The Legend of Ram, Judge Brack in Hedda Gabler,[14] and the solo performer in four monologues written and directed by Zubin Driver in Mumbai vs Mumbai.

In 2017, Smith re-joined director Toby Gough, choreographer Shruti Merchant[19] and team as the voice of Raj Pakoda in the light-hearted dance musical Taj Express.

[20] In 2020, along with Sonali Kulkarni and Shernaz Patel, he led the cast in the role of Superintendent Daniel D'Mello in the classic Whodunnit The Mirror Crack'd by Agatha Christie, adapted by Rachel Wagstaff in an Indian version by Ayeesha Menon, directed by the British director Melly Still and produced by international theatre producer Pádraig Cusack, staged at the Jamshed Bhabha Theatre at the National Centre for the Performing Arts (India) in Mumbai.

"[22] He is known for roles such as the Tibetan monk Lama Norbu in Paap (2003), directed by Pooja Bhatt and starring John Abraham, and as Tenzing in the film Frozen (2007), based in Leh and Ladakh.

Among the many independent films he has worked in are Shobhayatra (2004), where he played Jawaharlal Nehru, The Memsahib (2006), Mumbai Salsa (2007), Chase (2010), Lamhaa (2010), Impatient Vivek (2011), Tripura (2011), Ajita Suchitra Veera's Ballad of Rustom (2012), John Day (2013), and Dad...

[29] Smith appeared in the crime drama Baazaar (2018), as the Manipuri militant leader in Disney's Jagga Jasoos (2018),[30] the emergency period action film Baadshaho (2017),[31] comedy Happy Phirr Bhag Jayegi (2018)[32] and as a detective in the mystery thriller Badla directed by Sujoy Ghosh and starring Amitabh Bachchan and Taapsee Pannu.

[35] Smith has featured in several international productions that have achieved both critical and commercial success – One Night with the King (2007) with Omar Sharif and Peter O’Toole,[36] The Lunchbox (2013) with Irrfan Khan,[37] The Best Exotic Marigold Hotel (2011) and The Second Best Exotic Marigold Hotel (2015) with Judi Dench, Maggie Smith, Dev Patel, Bill Nighy and directed by John Madden[38] and Brahman Naman (2016), a Netflix original release[39] sex comedy, directed by Qaushiq Mukherjee, written by Naman Ramachandran[40] with Shashank Arora.

Prominent ones include ITV's Beecham House[46] which is Gurinder Chadha's Indian period piece, Netflix's Delhi Crime[47] directed by Richie Mehta on the Nirbhaya gang rape tragedy, renewed for Season 2.

Has also dubbed in Hindi feature films like Hanuman, House of Flying Daggers, The Boolean Conspiracy, Up, Bolt, James and the Giant Peach, Amar Chitra Katha, A Bug's Life, Shoot at Sight, Making of The Mahatma, Kung Fu Hustle and Red Cliff.