Owing to a serious knee injury he did not feature for Oxford in 1865,[1] but did make two first-class appearances later in the season for the Gentlemen of Middlesex and the Gentlemen of Marylebone Cricket Club. He resumed playing for Oxford in 1866, making a single appearance against Southgate, in addition to playing twice for Hampshire and the Marylebone Cricket Club (MCC).[3] The following season, he made four first-class appearances for Oxford University and one apiece for the MCC and the Gentlemen of Marylebone Cricket Club. Frederick made three final first-class appearances in 1868, playing one each for the Gentlemen of Marylebone Cricket Club, the MCC, and Hampshire.[3] He played the majority (10) of his first-class matches for Oxford, scoring 188 runs at an average of 11.05, with a highest score of 39. For Hampshire, he scored 171 runs and made his highest first-class score of 44. For the Gentlemen of the MCC and the MCC, he scored 153 runs and 95 runs respectively.[4] His overall first-class career consisted on 25 matches, in which he scored 635 runs at an average of 26.50.[5] As a batsman, he was described in Scores and Biographies as a "fine, free, and powerful hitter".[1] His four wickets all came in a single match for Hampshire against Middlesex in 1864.[6]
Frederick later served in the British Army. In April 1870, he purchased a commission with the rank of cornet into the 6th (Inniskilling) Dragoons,[7] before being promoted to lieutenant in November 1871.[8] In 1876, he was appointed as aide-de-camp to the commanding officer of the Cavalry Brigade at Aldershot Garrison.[9] He was promoted to captain in February 1878,[10] before retiring from active service in June 1881.[11] Frederick later served on the committee of the MCC in 1891 and from 1894 to 1898.[1] During his second stint on the committee, Frederick proposed a change to Law 53 of the Laws of Cricket, which regarded the follow-on. However, the proposed changes to Law 53 were not adopted by the committee as a whole.[12] In reports of MCC meetings in The Times in the 1890s, Frederick is identified as "Captain J. St J. Frederick".[13] Frederick died at Camberley on 10 September 1907 after what was described as "a long illness". The death notice records that he was a member of the Junior Carlton Club.[14] His nephew, Edward Frederick, was also a first-class cricketer.