Newcastle United paid £7,500 for Brennan's services in May 1946. Brennan made his debut as centre-half against Millwall on 31st August 1946. He played in 31 games that season. The team that year included Tommy Walker, Len Shackleton, Bobby Cowell, Jackie Milburn, Ernie Taylor, Joe Harvey and Charlie Wayman.
In the 1947-48 season Newcastle United won promotion to the First Division. Brennan was ever present that season. Paul Joannou points out in The Black 'n' White Alphabet: "He was cool-headed, steady and tough - a no nonsense defender who formed a terrific bond with the Geordie supporters for a decade." The 6 ft. 3in. tall Brennan, weighed over thirteen and a half stone and was known as the " Rock of Tyneside".
One of the men he marked, Nat Lofthouse, wrote about Brennan in his autobiography: "Big Frank, that man-mountain who oozes geniality and sportsmanship, is the kind of gentleman who does our great game so much good. If Frank puts you down in a shoulder charge he is always the first to give you a helping hand to your feet. He does not use his strength and weight unfairly. In the tackle his legs stretch out and flick the ball to safety just when you think you have broken away."
Newcastle United finished 4th in the the 1950-51 season. The club also enjoyed a good FA Cup run beating Bolton Wanderers (3-2), Stoke City (4-2), Bristol Rovers (3-1) and Wolverhampton Wanderers (2-1) to reach the final against Blackpool.
The defences were in control in the first-half. The deadlock was broken in the 50th minute when Jackie Milburn collected a pass from George Robledo to fire home. Five minutes later, Ernie Taylor cleverly back-heeled the ball and Milburn scored with a powerful shot from 25 yards. Brennan had won his first FA Cup winners' medal.
Newcastle United had another good FA Cup run in the 1951-52 season, beating Aston Villa (4-2), Tottenham Hotspur (3-0), Swansea City (1-0), Portsmouth (4-2), Blackburn Rovers (2-1) to reach the final against Arsenal. The London club had finished 3rd in the First Division championship whereas Newcastle managed only 8th place, their lowest position since promotion in 1948.
In the 19th minute Wally Barnes was injured in a tackle with Jackie Milburn. He tried to carry on but he was forced to leave the field in the 35 minute. Arsenal's ten men fought magnificently against the marauding Newcastle forwards. They held out until the 85th minute when George Robledo headed in a Milburn cross. Newcastle had become the first team to retain the FA Cup since Blackburn Rovers in 1891 and Brennan had won his second cup winners' medal.
Brennan remained the club's regular centre-half until he became involved in a dispute with the management of Newcastle United in 1955. As a result he was transferred to North Shields in March 1956. After retiring from football he worked as a football coach for the British Council.
In April 1967 Brennan became manager of North Shields and helped them to victory in the 1969 FA Amateur Cup. He was appointed manager of Darlington in August 1971 but stayed in the post for only three months before joining South Shields as their chief coach.
Frank Brennan died in 1997.
Frank Brennan, of Newcastle and Scotland, is another with a similar approach to the game. Big Frank, that man-mountain who oozes geniality and sportsmanship, is the kind of gentleman who does our great game so much good. If Frank puts you down in a shoulder charge he is always the first to give you a helping hand to your feet. He does not use his strength and weight unfairly. In the tackle his legs stretch out and flick the ball to safety just when you think you have broken away.
Frank Brennan has become accepted as so much part of English football that few people realize what a great footballer he is. As his opponent on football fields all over the country, I for one give him full marks for setting an example as a footballer and gentleman.