Although he obtained a degree in engineering at Southgate Technical College at his parents’ request, upon finishing his education, McBrain paid his rent by undertaking session work, before deciding to join his first “proper” band, “The 18th Fairfield Walk”, later known as “Peyton Bond”. A small pub band, which he decided was “never gonna go anywhere” as they only performed Otis Redding, The Beatles and The Who covers, McBrain soon left to join “The Wells Street Blues Band”, which renamed themselves “The Axe” in 1969. Although this group would play their own material, the band split up after an argument between the singer and the guitarist, and McBrain began playing with Billy Day, a singer and keyboardist, and Michael “Mickey” Lesley, a guitarist, in 1971. At that point, he was known as “Nicky”, a nickname given to him by his parents after his teddy bear, Nicholas, until an intoxicated Billy Day introduced him to Dick Asher, head of CBS Records, as “Neeko”, while they were recording at CBS Studios, Whitfield Street. McBrain liked the name, changing it to Nicko “so that it sounded more English”, and decided to keep it even after leaving the group. In 1973, McBrain performed on a single by Cockerel Chorus, “Nice One Cyril”, on the label Young Blood.

Also in 1973, McBrain played on a self-titled album by guitarist Gordon Giltrap. This is notable not only as McBrain’s album debut, but also because Giltrap in 1978 released an album called Fear of the Dark and used a font for his logo that is quite similar to the one used by Iron Maiden.

In 1975, he began playing with Streetwalkers, before joining Pat Travers, singer Jenny Darren, McKitty and then the French band, Trust, with whom he met Iron Maiden for the first time, while touring together in 1981. In 1982, the band asked McBrain to replace their previous drummer, Clive Burr, and, as news of Burr’s departure had not yet been announced, McBrain made his first appearance with Iron Maiden on German TV disguised as Eddie. He formed a close partnership with bassist, Steve Harris, and completed what many critics consider the band’s “definitive” line-up, releasing a series of gold and platinum selling albums throughout the 1980s.

McBrain is a long-time user of Paiste cymbals and currently plays British Drum Company drums, moving from Sonor Drums and having previously endorsed Premier. For A Matter of Life and Death he used his Ludwig metal shell LM 402 snare drum which was purchased in 1975, making it the oldest drum in his kit. He endorses Vic Firth signature drum sticks, also using them for his own drumming. As of 2016, McBrain also uses Remo drumheads, Sonor hardware, an LP cowbell and a DW 9000 single pedal (painted gold).

Steve Harris remarks that “…he can play all kinds of music. Drummers from other bands sit round the back of him to see what he’s doing, but he’s got his kit set so he doesn’t even look at what he’s hitting half the time”. After McBrain joined the band in 1982, Harris also noted how much easier playing with McBrain was for a songwriter, with Adrian Smith claiming that, “Steve loves playing with him. [They] used to work for hours going over these bass and drum patterns.”

In 1988, McBrain collaborated with Andrew Chapman on a book entitled Iron Maiden & Nicko McBrain’s Rhythms of the Beast, which was published by Warner Bros. Music in 1990. The book featured complete transcriptions of McBrain’s drum work on twelve classic Iron Maiden songs, including six live versions as recorded on the band’s 1985 album Live After Death. After selling internationally for several years, the book was taken out of print. Used copies are occasionally found for sale online.

In 1988, McBrain appeared as a guest on The Sooty Show, in which he played drums with Sooty and Sweep. In reference to his appearance on the show, McBrain’s drum kit has since been decorated with a Sooty puppet, which is often dressed accordingly with the band’s corresponding tours.

In 1991, McBrain released an instructional drum video, entitled Rhythms of the Beast (not related to the above book of the same name), which was re-released on DVD in 2010. The video features McBrain demonstrating his technique, and covers tuning, soloing and parts of the drum kit.

Although the band’s line-up changed during the 1990s, McBrain remained in Iron Maiden and, since the return of Adrian Smith and Bruce Dickinson in 1999, the group has undergone a resurgence in popularity, and are now considered by some as “bigger than ever”. When he’s not recording and touring with Iron Maiden, McBrain often plays with side projects including a band called McBrain Damage which played Iron Maiden covers. In March 2017, he was a guest drummer with the 8G Band on Late Night with Seth Meyers.

McBrain converted to Christianity in 1999 after an experience in the Spanish River Church, near his Boca Raton home. His wife, Rebecca, had been asking him to attend with her, and upon entering the church, McBrain soon found himself crying as he experienced a “calling”. Recounting the tale, he said “I just sat there thinking, ‘I didn’t drink last night… why can’t I stand?’ I had this love affair with Jesus going on in my heart.”

McBrain often employs the back end of his left hand drum stick to allow for more powerful “snare hits”. He is known for not using a double bass pedal, with Bruce Dickinson commenting that he refused to use one on “Where Eagles Dare”, considering them ‘undrummerish’. He claims to have only ever used a double pedal once on “Face in the Sand”, from Dance of Death, preferring to use a DW 5000 Accelerator single pedal. Since switching to the DW pedal in 2000, McBrain plays barefoot, stating that it gives him “more freedom.”

McBrain’s drumming has been an important element of Iron Maiden’s sound from 1983’s Piece of Mind onwards, with guitarist Adrian Smith remarking that, “he always had the chops and the technique, but in Maiden he really exploded, to the point where a lot of stuff we did after he joined was then founded on his playing, all those busy patterns he does, displaying tremendous technique.” As described in detail on the band’s 2004 documentary, Piece of Mind’s opening track, “Where Eagles Dare”, famously displays McBrain’s ability to use the single drum pedal very quickly, plus his rapid tom fills.

He is often considered among the best and most influential heavy metal/hard rock drummers of all time. In the 2008 Live After Death DVD, Steve Gadd, McBrain’s then drum technician, comments that, on the World Slavery Tour, some drummers would refer to McBrain as an ‘octopus’ after witnessing the way in which his stamina gives him the ability to use all of his large signature drum kit in concert.

In 2009, he opened a restaurant called Rock ‘N’ Roll Ribs in Coral Springs, Florida. The restaurant received positive reviews on an episode of Check, Please! South Florida and was awarded “Best Ribs of 2012” by New Times Broward-Palm Beach.

Since he is a lifelong enthusiast of Jaguar Cars, the manufacturer built a custom XKR-S model to McBrain’s specifications in 2012. In March 2018, Jaguar Land Rover Classic Works revealed a customized Jaguar XJ Series III for McBrain.

In 2015, McBrain stopped drinking alcohol after seeing an interview in which he had had too much wine and has remained sober to this day.

In 2018, he also launched a musical instrument store named Drum One in Manchester, England. The retailer specialises in drum kits and related merchandise. To promote the launch of the store, McBrain conducted an interview with Deep Purple drummer Ian Paice

In 2020, McBrain was inducted into the Modern Drummer Hall of Fame.