Whittington turned to coaching his former doubles partner and current professional Australian tennis player Alex Bolt for the 2022 summer.

In March 2012, Whittington began partnering Alex Bolt; the pair won three ITF doubles titles before June.

Whittington made his first appearance in the singles main draw of an ATP Challenger Tour at Caloundra in February 2012, losing narrowly in round 1.

In January 2013, Whittington was given a wild card into the Burnie Challenger where he reached the quarter-finals, before playing ITF tour across USA and Europe.

In August, Whittington lost in the final of the Chinese Taipei F1 before returning to Australia playing in ITF and Challenger circuit.

In January 2015, Whittington and Bolt made the final of the Onkaparinga Challenger, before reaching the third round of the Men's doubles.

Throughout the rest of 2015, Whittington began focussing on singles matches on the ATP Challenger tour, with limited success.

Whittington then played the Canberra and Launceston challenger events before winning his third and fourth ITF singles title in Mornington in March.

In July, Whittington was seeded for the first time in a Challenger Event at Gimcheon and reached his first final against Max Purcell.

In his ATP debut, he saved four match points against Luca Vanni, eventually winning 2–6, 7–6, 6–2 in two hours and 20 minutes.

Whittington played on the challenger tour before heading to USA in March, where he lost in qualifying for both Indian Wells and Miami Masters.

In the first round of qualifying, he recovered from a 1–4 deficit in the final set, saving break points in the sixth game against Stéphane Robert of France, to prevail 3–6, 7–5, 6–4.