He was hired at Jalan Ampas in 1948 as a general studio hand, and prop carpentry was the trade he was best at — he kept his union membership in the carpentry department for years after he was famous, and Hamzah Hussin recorded him still repairing soundstage props between takes at the height of his stardom.
B.S. Rajhans cast him as an extra in Chempaka that same year purely because of his face. It was tall, long, and incapable of concealing a reaction, and it turned out to be one of the most valuable comic instruments in the region.
Shamsuddin appeared with Ramlee in twenty-two films — more than anyone else in the ensemble — from Chinta in 1948 through Seniman Bujang Lapok in 1961. That range includes serious work: he was Hang Kasturi in Hang Tuah, holding his own in the martial choreography of a colour epic.
But his real contribution was rhythmic. He was the deadpan — the neurotic, morally anxious sceptic who doubted every scheme, panicked at every superstition, and delivered lines like "Alif Mim Nun Wau… Sarkis!" with total, guileless conviction. A single slow-burn look from Sudin could land a comic beat with no dialogue at all. He arrived slightly behind the beat on purpose, over and over, for twenty years, and it never once read as a mistake.
He stayed in Singapore with his family after the studio system collapsed, took work outside the industry, and accepted selective television roles. He was widely loved for exactly the thing his screen characters embodied: a complete absence of pretension. He died on 4 June 2013, aged eighty-four.
Beliau diambil bekerja di Jalan Ampas pada 1948 sebagai pekerja am studio, dan pertukangan kayu props ialah bidang yang paling dikuasainya — keahlian kesatuan sekerja di jabatan pertukangan kayu dikekalkannya bertahun-tahun selepas namanya masyhur, dan Hamzah Hussin merakam beliau masih membaiki props pentas penggambaran di celah rakaman ketika berada di kemuncak kegemilangannya.
B.S. Rajhans memberinya watak pelakon tambahan dalam Chempaka pada tahun yang sama semata-mata kerana wajahnya. Wajah itu tinggi, panjang, dan tidak mampu menyembunyikan sebarang reaksi, lalu ternyata menjadi antara alat komedi paling berharga di rantau ini.
Shamsuddin muncul bersama Ramlee dalam dua puluh dua buah filem — lebih daripada sesiapa pun dalam ensembel itu — dari Chinta pada 1948 hingga Seniman Bujang Lapok pada 1961. Kepelbagaian itu merangkumi karya serius: beliau Hang Kasturi dalam Hang Tuah, berdiri sama tinggi dalam koreografi pertarungan sebuah epik berwarna.
Namun sumbangan sebenarnya bersifat rentak. Beliaulah suara bersahaja itu — pemikir yang neurotik dan gelisah moralnya, yang meragui setiap muslihat, cemas dengan setiap tahyul, dan melafazkan dialog seperti "Alif Mim Nun Wau… Sarkis!" dengan keyakinan yang tulen dan tanpa helah. Satu pandangan lambat daripada Sudin mampu menjatuhkan sesebuah beat komedi tanpa sepatah dialog pun. Beliau tiba sedikit di belakang rentak secara sengaja, berulang kali, selama dua puluh tahun, dan tidak sekali pun ia terbaca sebagai kesilapan.
Beliau menetap di Singapura bersama keluarganya selepas sistem studio runtuh, bekerja di luar industri hiburan, dan menerima tawaran lakonan televisyen secara terpilih. Beliau amat disayangi ramai kerana perkara yang sama yang dilambangkan watak-watak layar peraknya: ketiadaan sifat berlagak sama sekali. Beliau meninggal dunia pada 4 Jun 2013, pada usia lapan puluh empat tahun.