He made his second appearance at senior level on 17 March, when he replaced Paul Marshall 49 minutes into a 3–2 defeat away to Crawley Town; manager Micky Adams put him on as centre-back Clayton McDonald had just been sent off.

[9] McDonald's subsequent suspension gave Davis the opportunity to start against Hereford United three days later, Adams saying "he'll either sink or swim".

[11] However, he was sent off 69 minutes into the next match for a professional foul on Torquay United's Rene Howe; the penalty kick was converted to cost Vale a 2–1 away defeat.

[12] With Clayton McDonald facing legal issues, Davis was given an extended run in the team towards the end of the 2011–12 season, thus securing the 18-year-old apprentice his first professional contract.

[20] Having failed to make an appearance for Port Vale at the start of the 2013–14 season, he was loaned out to Conference Premier club Luton Town in November 2013.

[22] Luton manager John Still requested an extension to the loan but Micky Adams recalled Davis to provide cover for the injured Richard Duffy.

[23] On 11 January an injury crisis meant that he started in an inexperienced centre-back partnership with 19-year-old Jack Grimmer as Vale lost 2–0 away to league leaders Brentford.

"[26] He earned a place on the Football League Team of the Week for his performance as "a commanding figure" in a 0–0 draw at Shrewsbury Town on 15 February.

He was ruled out of action for three months, before he was recalled to the first-team by new manager Neil Aspin in December to replace the suspended James Gibbons at right back.

I left it at its lowest point, spiralling towards administration under Norman Smurthwaite, along with a disgruntled fan-base and a group of players that had lost faith in its leadership.

[51] On 22 February 2014, for 33 minutes of a match at Port Vale, Harry and Joe Davis played on opposite teams against each other, while their father watched as manager of Crewe.

[52][53] Joe later stated that the experience had a negative psychological effect on him and also recalled that manager Micky Adams had previously banned him from the training ground in games against Crewe so that he wouldn't divulge tactics to his father.